CD4 and neoplasm: One of such immune subsets is the tumor-associated macrophages (TAMs) which are polarized into M2 macrophage phenotype by IL-10, TGF-β, IL-4, or IL-13 present in the TME, and drive tumor progression by supporting angiogenesis and recruitment of CD4+FoxP3+ T regulatory cells (Tregs) (Figure 1) (35, 36).