Indeed, some dMMR-MSI-H colorectal tumors that initially displayed active cytotoxic CD8+ T cell (CTL) responses have been shown to raise immunosuppressive molecules such as PD-1, PD-L1 or CTLA-4 to counterbalance the cytotoxic environment, inducing tumor immune evasion [32]. This evidence concerns the gene CTLA4 and colorectal neoplasm.