CD44 and neoplasm: They are able to 1) reduce the expression of M1 macrophages inhibitors CD200 and CD44 blocking macrophage M2 polarization and phagocytic activity, 2) produce several cytokines in the TME, like Transforming Growth Factor β (TGF-β), IL-4, IL-6, IL-10, paralyzing the immune system responses, 3) convert a subset of immature myeloid DCs into TGF-β-secreting cells, thus driving expansion of immunosuppressive regulatory T cells (Tregs) in lymphoid organs of tumor bearing mice [27,28], and 4) attract Tregs and Myeloid-Derived Stem Cells (MDSC), facilitating CSCs spreading and metastatization [29].