At a Thursday press briefing on Thursday, incoming Press Secretary Sean Spicer defended Trump's diverse and qualified cabinet. Yet, he also noted that the president-elect plans to keep at least 50 Obama appointees - temporarily.
For instance, Adam Szubin will serve as acting Treasury secretary until Trump’s nominee Steven Mnuchin is confirmed. Mnuchin is currently undergoing confirmation hearings on Capitol Hill.
Other officials in the White House Military Office, the Pentagon, the Drug Enforcement Administration and other agencies will carry over from the Obama years. You can see a full list here.
Spicer told the press that the Trump transition team was very grateful toward President Obama and Vice President Biden for their cooperation. He didn't have such nice things to say about stubborn congressional Democrats.