In CRC, anti-PD-1/PD-L1 therapy, such as pembrolizumab, has also been approved in a subgroup of patients, namely mismatch repair deficient (dMMR) ones, which present higher PD-L1 expression when compared with MMR proficient (pMMR) carcinomas [125,133,150,151,152]. This evidence concerns the gene CD274 and carcinoma.