CD274 and head and neck squamous cell carcinoma: The Food and Drug Administration (FDA) recently approved nivolumab (anti-programmed cell death protein 1 (PD1) antibody) and pembrolizumab (anti programmed cell death protein ligand 1 (PD-L1) as second line treatments of R/M HNSCC patients and pembrolizumab in first-line in PD-L1 (combined positive score ≥ 1%) tumor-positive patients [9,10].