As there is a risk of severe bleeding with this study drug, participants must be willing to receive blood transfusions if medically necessary for their own safety. Participants must be able to receive blood transfusions 68 Abbreviated Title: Neoadjuvant IO for HNSCC Version Date: August 31, 2022 in order to minimize the risks of receiving M7824. Another reason for this is that including these patients could compromise the scientific validity of the study.