Ki67 immunohistochemical staining showed that anti-PD-1 alone had no inhibitory effect on tumor cell proliferation, while the inhibitory effect of CDDP on Ki67 staining was small but not significant, and CDDP combined with anti-PD-1 has a synergistic inhibitory effect on Ki67 staining (Fig. 5G). The gene discussed is PDCD1; the disease is neoplasm.