Among these various types of immunotherapies with different molecular targets, therapeutically targeting immune inhibitory checkpoints through the blockade of programmed cell death 1 (PD-1) or programmed cell death ligand 1 (PD-L1) has unprecedentedly led to durable responses across a broad range of human cancers, which was then widely used in the clinical practice of various solid tumors (12). This evidence concerns the gene PDCD1 and cancer.