"Dr. Cohen is taking over an agency that is in transition. Her predecessor, Dr. Walensky, who began serving at the start of the Biden administration and stepped down in June, commissioned a review of the C.D.C. that identified serious weaknesses in areas ranging from testing to data collection to communications. She then initiated an overhaul of the agency."

https://www.nytimes.com/2023/12/15/us/politics/mandy-cohen-cdc-director.html