CD8+ T cells can kill tumor cells with cytotoxic molecules such as granzyme and perforin.[44] Macrophages exist in 2 polarization states, among which classically activated macrophages (M1) produce pro-inflammatory cytokines and reactive oxygen/nitrogen species, which are essential for host defense and tumor cell killing.[45] In the C3 subtype, the increase in CD8+ T cells, M1 macrophages, and monocytes, and the decrease in Treg cells may be another potential mechanism for the better prognosis of the C3 subtype. The gene discussed is PRF1; the disease is neoplasm.