Political appointees in the Department of Health and Human services are objecting to reports on the COVID-19 pandemic from the Centers for Disease Control, and are trying to exercise editorial control of future reports. That's the bottom line of an extensive report from Politico that was based on both internal emails and interviews with people in the organization. The problems apparently stem from the fact-based reports from the CDC running counter to the Trump administration's preferred narrative about the spread of the pandemic and the appropriate public health responses.
The CDC documents at issue are termed Morbidity and Mortality Weekly Report, which provide rapid summaries of the state of our knowledge about public health issues. Typically, they're the product of a CDC-backed investigation into a known issue; in the past, they've focused on things like outbreaks of food-borne illnesses. While they don't have the weight of peer-reviewed literature, they're widely considered to be scientifically reliable, and their rapid publication makes them a valuable resource for public health officials.
It's easy to see how the reports' accurate information could be viewed as counter to the preferred message of the Trump administration. Trump has made reopening schools a centerpiece of his pandemic policy, but CDC Morbidity and Mortality Weekly reports have described how SARS-CoV-2 can spread rapidly in a school-aged population, how young children can bring the disease home and pass it on to adults, and how children can suffer severe complications from the disease.