In hepatocellular carcinoma (HCC), single-cell sequencing results have shown that apoc1 promotes the transformation of M2 macrophages into M1 macrophages, thus promoting the metastasis of HCC, reshaping the tumor immune microenvironment, and improving the immunotherapy effect of anti-PD-1 against HCC [13]. The gene discussed is APOC1; the disease is hepatocellular carcinoma.