Tumor-mediated suppressive factors such as extracellular TME stimuli (hyaluronan accumulation, vascular collapse, hypoxia, low pH, adenosine-rich medium, cytokines, TGF-β, prostaglandin-E2, IL-dependent STAT3 activation, etc.)and suppressive immune cells (Treg, MDSCs and TAMs) also contribute to the inhibition of NK cell activity [206,226,227]. Here, TGFB1 is linked to neoplasm.