CTLA4 and neoplasm: However, despite the increased expression of CTLA-4 on Tregs in the tumor microenvironment (TME) of cancer patients and pre-clinical evidence showing the capacity of ipilimumab to deplete Tregs via ADCC-dependent mechanisms, ipilimumab is thought to induce infiltration of intratumoral CD4+ and CD8+ effector T cells without depleting Tregs in the TME in humans (106).