Polzastobart (JTX-8064), a humanized IgG4 monoclonal antibody, functions as an antagonist selectively targeting LILRB2. It inhibits its interaction with both classical and non-classical MHC I molecules. By preventing LILRB2 from binding to HLA-A/B and HLA-G, which are associated with immunotolerance in cancer cells, Polzastobart promotes the production of pro-inflammatory cytokines in macrophages, thereby serving as a macrophage immune checkpoint inhibitor [1].