PDCD1 and neoplasm: In addition, combination of SRE and anti-PD-1 antibodies remarkably increased infiltration of CD8+ T cells in tumor tissues more than either 300 mg/kg SRE alone or anti-PD-1 antibodies alone, as well as increasingly released PRF1 granules of tumor-infiltrating CD8+ T cells via PD-1/PD-L1 blockade in the tumor microenvironment.