CD4 and neoplasm: The innate and adaptive immune systems collaborate to identify and eradicate tumor cells, with distinct roles played by various immune cell types, including CD4 + T-helper cells (e.g., TH1, TH2, and TH17 cells), CD8 + cytotoxic T cells, γδT cells, natural killer (NK) cells, and natural killer T (NKT) cells24.