FOXP3 and head and neck squamous cell carcinoma: In order to characterize the functional status of NK/T cell subgroups in HNSCC, we first further subdivided NK/T cells into 5 subgroups: CCR7 + Naive CD4 T cells, FOXP3 + IL1R2 + Tregs, TRGC2 + NK/T cells, Proliferating CD8 T cells, and TRDC + NK/T cells (Fig. 5A).