First, based on TCGA data, we demonstrated a significant correlation between APOL3 and cytotoxic cytokine-associated gene expression; next, based on single-cell RNA sequence, we found that APOL3 expression were correlated with tumor microenvironment infiltration; Furthermore, based on IF and IHC analysis, APOL3 was significantly correlated with LDHA expression and CD8+ T cell infiltration. This evidence concerns the gene CD8A and neoplasm.