TIGIT and melanoma: Importantly, CX3CR1 expression in human melanoma-infiltrating CD8+ T cells was inversely correlated with the expression of PDCD1, TIGIT, and HAVCR2 (Fig. 1E; Supplementary Table S3), which is consistent with our previous flow cytometric analyses of mouse melanoma-specific CD8+ T cells and human melanoma CD8+ TILs (15).