President-elect Donald Trump and his transition team are beginning to make announcements about senior-level Cabinet officials and staff who will be part of his administration when it begins in January. Trump is expected to nominate South Dakota Gov. Kristi Noem to serve as homeland security secretary and Florida Sen. Marco Rubio to be secretary of state, multiple sources tell NBC News. The list below of proposed picks by Trump includes choices he has announced officially and expected picks based on NBC News reporting. Picks announced by Trump U.S. ambassador to the United Nations: Rep. Elise Stefanik of New York Administrator of the Environmental Protection Agency: former Rep. Lee Zeldin “Border Czar”: former ICE director Tom Homan White House Chief of Staff: Susie Wiles Expected or apparent picks Homeland Security secretary: South Dakota Gov. Kristi Noem Secretary of State: Sen. Marco Rubio of Florida Deputy chief of staff for policy: Stephen Miller National security adviser: Rep. Mike Waltz of Florida Once in office in January, Trump can formally nominate officials for roles that require Senate confirmation, including Cabinet positions.