PDCD1 and cancer: In various cancers, according to computational analyses, the TIGIT expression profile was related to the immune infiltration level, coupled with the expression of other IRs, including LAG3, CTLA4, PD-1, PD-L1, PD-L2, and it is related to tumor mutation burden (TMB), microsatellite instability (MSI), mismatch repair (MMR), and DNA methyltransferases (DNMTs) gene alterations in different tumors (122).