ESR2 and neoplasm: Combining Erb-IL-21 with anti-PD-L1(Programmed Cell Death Ligand 1) antibody as treatment for mice bearing tumors dramatically reduced the tumor volume and enhanced survival, whereas the administration of Erb-IL-21 with anti-CTLA-4 (Cytotoxic T-lymphocyte-associated protein 4) induced the tumor clearance in all mice (60).