TIGIT is expressed on human tumor-infiltrating CD8+ T cells, NK cells, Th and Treg cells in melanoma (54, 55), NSCLC (56, 57), colon cancer (52), HCC (31, 58), gastric cancer (59), glioblastoma (60) and hematological malignancies (42, 61, 62). This evidence concerns the gene CD8A and neoplasm.