PDCD1 and neoplasm: Numerous studies have demonstrated that blocking VEGFA/VEGFR signal pathway could induce tumor regression by not only inhibiting the proliferation of endothelial cells and the formation of new blood vessels in the TME but also improving the infiltration of cytotoxic lymphocytes into the TME, while PD-1/PD-L1 pathway blockade could activate the infiltrated cytotoxic lymphocytes by removing the immunosuppressive effect mediated by this pathway (22).