Monalizumab (also known as IPH-2201) is an investigational, humanized IgG4 monoclonal antibody that targets the immune checkpoint receptor NKG2A (CD159a). NKG2A forms a heterodimer with CD94 and is expressed on natural killer (NK) cells and a subset of CD8+ T cells. It binds to the non-classical MHC class I molecule HLA-E, which is often upregulated on tumor cells and infected cells. By blocking the interaction between NKG2A and HLA-E, monalizumab releases the inhibitory signal on NK cells and T cells, thereby enhancing their cytotoxic activity against tumors. It is being developed as an immune checkpoint inhibitor for the treatment of advanced solid tumors and hematologic malignancies, often in combination with other therapies (e.g., anti-PD-L1 antibodies).