CD4 and neoplasm: One of the ways chemokines and cytokines can mediate this is by facilitating the recruitment of immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs), T regulatory cells (Tregs), tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), etc., thus, creating an immunosuppressive TME and inhibiting anti-tumor immune responses carried out by CD4+/CD8+ T lymphocytes and natural killer (NK) cells (Fig. 2).