CD4 and head and neck squamous cell carcinoma: In head and neck squamous cell carcinoma, curcumin restored the cytotoxic function of effector T cells by modulating the expression of PD-1 and TIM-3 on CD4+or CD8+ T cells and CD4+CD25+Foxp3+ Tregs, promoting the expression of IFN-γ and granzyme B to exert its anticancer effects.