CD274 and head and neck squamous cell carcinoma: A Phase III study of pembrolizumab alone or with chemotherapy versus cetuximab with chemotherapy for recurrent or metastatic HNSCC showed that pembrolizumab plus platinum and 5-fluorouracil is an appropriate first-line treatment for recurrent or metastatic HNSCC, and pembrolizumab monotherapy is an appropriate first-line treatment for PD-L1-positive recurrent or metastatic HNSCC [55].