In head and neck squamous cell carcinoma (HNSCC), curcumin increased tumor infiltrating lymphocytes (TILs) and decreased the expression of mucus structural domain 3 (TIM-3) cells and programmed cell death protein 1 (PD-1), which enhances the possibility of targeted therapy for HNSCC (131). Here, PDCD1 is linked to head and neck squamous cell carcinoma.