TGFB1 and neoplasm: Collectively, nutrient competition (glucose, glutamine, arginine, methionine, tryptophan), secretion of suppressive metabolites (lactate, Kyn, adenosine), cytokine signaling (TGF-β, IL-10), and metabolic symbiosis between tumor cells and TAMs create a resilient immunosuppressive niche (96, 97).