PDCD1 and colorectal carcinoma: In addition to immunorecognition, T cell infiltration is also fundamental for PD-1-blocking therapy; thus, the immunoscore based on the calculation of two lymphocyte populations (CD3/CD45-CD8 or CD8/CD45 populations) in the center and invasive margins of the tumor has been attractive for predicting the drug response and has acted as a reliable CRC classifier and recurrence estimator; however, it is waiting for further clinical validation.422–424