CD274 and head and neck squamous cell carcinoma: The degree of PD‐L1 expression is used as a predictive biomarker that has guided different treatment protocols—pembrolizumab in combination with platinum and fluorouracil is used for all patients (biomarker‐unspecified) with R/M HNSCC, and pembrolizumab monotherapy is used for patients with R/M HNSCC, whose tumors express a PD‐L1 combined positive score ≥ 1 [8, 9].