"Under federal law, Trump doesn’t have the power to directly fire Fauci, a career civil servant, and remove him from government. And while Trump could try ordering his political appointees to dismiss the director of the National Institute of Allergy and Infectious Diseases, Fauci could appeal – a time-consuming process."
https://www.cnn.com/2020/07/13/politics/can-trump-fire-fauci/index.html