PDCD1 and head and neck squamous cell carcinoma: Presently, the FDA has approved several other PD-1/PD-L1 inhibitors, including atezolizumab (Tecentriq®, Roche), durvalumab (Imfinzi®, AstraZeneca), and avelumab (Bavencio®, Merck, Pfizer, Eli Lilly and Company) for the treatment of at least ten cancer types, including melanoma, NSCLC, head and neck squamous cell carcinoma, Hodgkin’s lymphoma, urothelial carcinoma, gastric or gastroesophageal junction cancer, cervical cancer, large B-cell lymphoma, Merkel cell carcinoma, and CRC.