The results showed that APS, administered by intraperitoneal injection at doses of 100–400 mg/kg for 12 days or by pre-treating cells at concentrations of 0.1–1 mg/mL for 4 h, inhibited tumour growth in a dose-dependent manner, downregulated PD-L1 expression, and increased CD8+ T cell infiltration. The gene discussed is CD8A; the disease is neoplasm.