As a result, cells produce and release large amounts of inflammatory factors, chemokines, which play a role in the formation of an immunosuppressive microenvironment by enhancing immunosuppressive cell recruitment and function, promoting macrophage polarization to the M2 phenotype, inhibiting effector T-cell function, increasing the level of programmed cell death protein-1/programmed cell death ligand-1(PD-1/PD-L1) expression, and remodeling tumor stroma and fibrosis (21–23). This evidence concerns the gene PDCD1 and neoplasm.