A previous study showed that Treg cells from both the tumor microenvironment and dLNs in HNSCC patients exhibited a CCR6+ effector Treg cell phenotype, and CCR6+ Treg cells expressed a higher level of FOXP3 than CCR6− Treg cells, which indicated a stronger suppressive function.32 Here, FOXP3 is linked to head and neck squamous cell carcinoma.