CTLA4 and neoplasm: In tumor immunity, Tregs are involved in tumor development and progression as they impair T cell function through the secretion of immune suppressive cytokines (IL-10, TGF-β, IL-35), consumption of IL-2 that leads to its depletion in the TME, and expression of inhibitory checkpoint receptor cytotoxic T lymphocyte-associated protein (CTLA-4).