This pattern suggests that the reason why terminally exhausted CD8+ T cells failed to respond to anti-PD1 therapy might be not only the co-expression of multiple inhibitors on CD8+ T cells themselves but also the tumor microenvironment of colorectal tumor in which those terminally exhausted CD8+ T cells may be infiltrated with myeloid-derived suppressor cells. This evidence concerns the gene PDCD1 and colorectal neoplasm.