Importantly, high expression of TIGIT, PD-1, LAG3, IDO1, CTLA-4, PDCD1LG2 (PDL2), CD274 (PD-L1) and HAVCR2, was significantly correlated (p < 0.001, Pearson’s rho> 0.65) with an increased immune cytolytic activity in both CRC datasets. Here, IDO1 is linked to colorectal carcinoma.