This review analyzes the biological aspect and presents preclinical and clinical data of CTLA-4, PD-1/PD-L1, and other new inhibitory immune checkpoints such as lymphocyte-activation gene 3 (LAG-3) and T-cell immunoglobulin- and mucin domain-3-containing molecule 3 (TIM-3) in the induction and progression of CRC. The gene discussed is PDCD1; the disease is colorectal carcinoma.