Competitive short peptide inhibitors, e.g., CPP-S1, have shown some antitumor effects, but their poor stability in mice may lead to insufficient effective concentration and affect efficacy [21], 3.natural compounds (e.g., benzocuproine C [490]), have been used to reduce PD-L1 levels and activate anti-tumor immune responses. The gene discussed is CD274; the disease is neoplasm.