A hinge stabilized immunoglobulin G4 (IgG4) tetravalent bispecific antibody-like protein directed against the human negative immunoregulatory checkpoint receptors programmed cell death protein 1 (PD-1; PDCD1; CD279) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA4; CTLA-4), with potential immune checkpoint inhibitory and antineoplastic activities. Upon administration, lorigerlimab specifically binds to both PD-1 and CTLA4 expressed on tumor-infiltrating lymphocytes (TILs) and inhibits the PD-1- and CTLA4-mediated downregulation of T-cell activation and proliferation. Dual blockade of PD1 and CTLA4 pathways provides enhanced activity against PD1+CTLA4+ double positive cells and may increase T-cell activation and proliferation compared to the blockade of either immune checkpoint alone.