This wealth of biological information on the mechanisms of MMRd immunogenicity has been paralleled by the clinical development of ICB in the management of early [48, 49] and advanced CRC [50–52], leading to the approval of anti-PD-1 +/- anti-CTLA-4 blocking antibodies in the treatment of MMRd/MSI-H CRCs. Here, CTLA4 is linked to colorectal carcinoma.