In contrast, APOBEC3A/3G/3H were positively correlated with the infiltration level of many kinds of immunoreactive tumor-infiltrating cells, including Tem_CD4, Tem_CD8 and NK cells (Supplementary Figure S1), and positively correlated with the expression level of most immunomodulators (immunoenhancers, MHC molecules, chemokines and chemokine receptors) in PAAD (Figures 4A,C–F), indicating that APOBEC3A/3G/3H may play immune-promoting roles in the PAAD tumor microenvironment. This evidence concerns the gene CD4 and neoplasm.