This study is for patients that have been diagnosed with with resectable High-risk Locally Advanced Cutaneous Squamous Cell Carcinoma (LA cSCC). The investigational drug used in this study is Pembrolizumab. The purposes of this study are to: determine how well pembrolizumab keeps the cancer from coming back or spreading as compared to placebo, determine if giving pembrolizumab after surgery and radiation helps patients live longer, and to test the safety of the study drug and see how patients' bodies handle it. Participants can expect to be in this study for about 8 years. This includes the time that participants will be on study drug and in follow up to see if the cancer has come back or spread.

This is a study that looks at the use of anti-platelet therapy and chemotherapy in patients with recurrent or metastatic squamous cell carcinoma of the head and neck (HNSCC). Anti-platelet therapy is the use of drugs that reduce the blood's ability to form clots. The overall goal of this study is to see if this therapy combination can increase the body's ability to fight the disease.