Separately, Biden has reportedly picked Dr. Rochelle Walensky, a Harvard infectious disease expert, to replace Dr. Robert Redfield as CDC director.

President-elect Joe Biden will nominate California Attorney General Xavier Becerra to lead the health and human services department, a critical appointment amid a global pandemic that has killed more than 280,000 in the U.S. alone.
Separately, Biden picked a Harvard infectious disease expert, Dr. Rochelle Walensky, to replace Dr. Robert Redfield as head of the Centers for Disease Control and Prevention.
If confirmed by the Senate, Becerra, 62, will be the first Latino to head the Department of Health and Human Services, a $1-trillion-plus agency with 80,000 employees and a portfolio that includes drugs and vaccines, leading-edge medical research and health insurance programs covering more than 130 million Americans.
Becerra’s nomination, which was first reported by The New York Times and confirmed by The Associated Press, as Health and Human Services secretary comes as Biden has faced increasing pressure to add more diversity to his administration.
Two people anonymously confirmed the choice of Walensky to the Associated Press. The selection was first reported by Politico. The post of CDC director does not require Senate confirmation.
She would replace Redfield, who accurately told the public that coronavirus vaccines would not be available for most people until next year, only to be disparaged by Trump as confused. Walensky is a leading infectious disease specialist at Massachusetts General Hospital, and has devoted her career to combatting HIV/AIDS.
Long considered to be a leading contender for attorney general, Becerra has been one of the most aggressive opponents of the Trump administration having sponsored a wave of legal actions challenging environmental, immigration and Census policies.
Congressional Hispanic Caucus Chairman Joaquin Castro lauded the former congressman’s selection in a statement Sunday. 
“In this moment of crisis with COVID-19 devastating Latino communities, the Congressional Hispanic Caucus is proud that Californias Attorney General Xavier Becerra, a dedicated public servant, will be nominated by President-Elect Biden to lead to U.S. Department of Health and Human Services,” the statement said.
“Becerra has lived the American Dream and he is a champion for working families, which we saw firsthand during his tenure as a leader in Congress. We welcome the news of Becerras nomination, and the CHC is encouraging President-Elect Biden to appoint five Latinos in the Cabinet, including Latinas in prominent positions,” it read. “We will continue to work in partnership with the Biden-Harris transition team to assemble the most diverse administration in American history.”
Becerra, if confirmed, would take on a crucial role in the Biden administration, leading its response to the coronavirus pandemic. 
Overseeing the coronavirus response will be the most complicated task Becerra has ever contemplated. By next year, the U.S. will be engaged in a mass vaccination campaign, the groundwork for which has been laid under the Trump administration. Although the vaccines appear promising, its impossible to tell how well things will go when its time to get shots in the arms of millions of Americans.
The core components of HHS are the boots-on-the-ground part of the governments coronavirus response. The Food and Drug Administration oversees vaccines and treatments, while much of the underlying scientific and medical research comes from the National Institutes of Health. The Centers for Disease Control and Prevention takes the lead in detecting and containing the spread of diseases. The Centers for Medicare and Medicaid Services provides insurance coverage for more than 1 in 3 Americans, including vulnerable seniors, as well as many children and low-income people.
Under Trump, CDC was relegated to a lesser role after agency scientists issued a stark early warning that contradicted Trumps assurances the virus was under control. The FDA was the target of repeated attacks from a president who suspected its scientists were politically motivated and who also wanted them to rubber-stamp unproven treatments.
Becerra was also reportedly on the shortlist to be tapped as U.S. attorney general, and his name has been mentioned as someone California Gov. Gavin Newsom might tap to replace Kamala Harris Biden’s running mate  in the U.S. Senate.  
The move to nominate Becerra for HHS secretary will put the longtime former Democratic congressman in charge of an agency he openly fought against during the Trump administration with multiple lawsuits defending former President Barack Obama’s signature health insurance program. 
The Trump administration sought to repeal the Affordable Care Act, also known as  Obamacare, both legislatively and in the courts. The insurance program is federally administered by the HHS.  
As California’s attorney general, Becerra has led the coalition of Democratic states defending Obamacare from the Trump administration’s latest effort to overturn it, a legal case awaiting a Supreme Court decision next year.
A former senior House Democrat, Becerra played a role in steering the Obama health law through Congress in 2009 and 2010. At the time, he told reporters that one of the primary motivations for him was having tens of thousands of uninsured people in his Southern California district.
Besides the court struggles over the health care law, one of Becerra’s other high-profile legal battles against the Trump administration was in defense of the Deferred Action for Childhood Arrivals, or DACA, program, which allows undocumented immigrants who were brought to the United States as children to stay and work in the country. 
About a quarter of the nations DACA recipients an estimated 200,000 Dreamers reside in California, Becerra said.
While some leaders in other states may not wish to stand with our young immigrant brothers and sisters, daughters and sons, we do, he said in 2017. Instead of scapegoating our kids, we should be ensuring that they can fulfill their potential.
Becerra also took aim at the Trump administration’s much-hyped U.S.-Mexico border wall, which he said “threatens the state of California’s economic, procedural and sovereign interests and will harm the state’s natural resources.”
Im still trying to figure out who believes that a medieval situation to fix our broken immigration system is what we need, Becerra said.
More:President-elect Biden seeks a diverse Cabinet. Here’s who will join his administration and who might be top contenders
Becerra’s combative stance against the former administration drew praise from Democrats and scorn from Republicans. 
Republican Steven Bailey, an El Dorado County judge who ran against Becerra for California attorney general in 2018, called  Becerras legal challenges to the Trump administration frivolous lawsuits that have no basis.
Its time that the attorney general was focused on Californias problems, not Washingtons problems, Bailey said.
But Becerra pushed back against that criticism. 
My job as AG is to protect California families, to protect our values, and to protect our resources, Becerra said in 2018. 
In addition to his combative relationship with the Trump administration, Becerra often clashed with the state’s biggest technology companies such as Facebook, Google and Apple over their handling of user privacy, election interference, and competitive practices. 
Becerra just didn’t battle with the Trump administration or high-tech companies during his time heading California’s justice department.
In 2017, Becerra blocked state-funded travel to Alabama, Mississippi and Kentucky in response to what he considered anti-LGBT rights laws enacted in those states. 
Becerra, one of the highest-ranking Latinos in Congress and a prominent surrogate for Democrat Hillary Clintons presidential campaign in 2016, represented parts of Los Angeles for 24 years before he was appointed California attorney general by then-Gov. Jerry Brown in 2017, replacing Harris, who was elected to the United States Senate. 
In 2018, Becerra was elected to a full four-year term as attorney general by California voters. 
Becerra grew up in Sacramento as a son of poor, working immigrants. He noted that he was the first in his family to graduate from college, obtaining both bachelors and law degrees from Stanford University.
Becerra worked as a deputy attorney general for three years before beginning his political career as a state Assemblyman in 1990. He was elected to Congress in 1992.
Contributing: The Associated Press