The expression of EFHD2 was closely related to immune infiltration, among which 18 cancers were significantly correlated with CD8 T cells, 14 cancers were significantly correlated with regulatory T cells (Tregs) cells, 15 cancers were significantly correlated with CD4 memory activated T cells, and EFHD2 was significantly correlated with common tumor-related regulatory genes such as TGFBETASIGNALING, TNFASIGNALING, hypoxia, scorch death, DNA repair, autophagy, and iron death-related genes. This evidence concerns the gene CD8A and cancer.