Sintilimab is a programmed cell death protein 1 (PD-1) inhibitor that produces a tumor immune response by binding to PD-1, blocking the binding of PD-1 to programmed cell death ligand 1 (PD-L1) and programmed cell death ligand 2 (PD-L2), relieving the immunologic suppression and activating the function of T cells. This evidence concerns the gene PDCD1 and neoplasm.