PDCD1 and head and neck squamous cell carcinoma: The results of a recent study performed on a small number of PD-L1-positive oral HNSCC patients indicate that the combination of PD-1 inhibitors (Nivolumab or Sintilimab), anti-EGFR targeted therapy (Nimotuzumab) and chemotherapy (Paclitaxel) could improve the response rate and survival outcome (161).