CTLA4 and neoplasm: The combination regimen of either anti-CTLA-4 Ab or anti-PD-L1 Ab with pegzilarginase induced greater anti-tumor activity than either IO monotherapy, including an increase in complete responses (CRs) in anti- PD-L1 Ab studies (37.5% CRs in combination arm vs. 0% in anti-PD-L1 Ab arm).