CXCR6 and head and neck squamous cell carcinoma: As in the case of HNSCC patients, we found a positive correlation between the gene expression of CD2, CD3D, CD3E, and CXCR6 and CD8+ T cells (central and effector memory subpopulations), and the strongest correlation was observed for the central memory CD8+ T cells (CD2: Rho=0.881, CD3D: Rho=0.883, CD3E: Rho=0.896, and CXCR6: Rho=0.850) (Figure 6).