CD4 and central nervous system cancer: Infiltrating immune cells in the TME of gliomas consist of microglia/macrophages, CD4+ T cells, MDSCs, regulatory T cells (Tregs) and granulocytes; microglia and MDSCs are the most common factors (Gieryng et al., 2017); the presence of these factors is responsible for the inefficacious immune response in patients with glioblastoma (Marvel and Gabrilovich, 2015).