There was a significant increase in the intensity of infiltration of NK cells, CD4+T cells, and CD8+T cells in tumors from the FeNP/CpG groups compared with that in the FeNP, CpG, and NS groups (P < 0.005), which suggests that FeNP/CpG not only stimulates a higher immune response but also alters the tumor microenvironment by activating more immune cells into the tumor tissues. The gene discussed is CD8A; the disease is neoplasm.