Signal Regulatory Protein Alpha (SIRPα), an inhibitory receptor predominantly expressed on myeloid cells such as macrophages, dendritic cells, and neutrophils. The binding of its ligand, CD47—which is often overexpressed on cancer cells—to SIRPα initiates a signaling cascade that results in the inhibition of phagocytosis. This CD47-SIRPα interaction is a critical immune checkpoint that allows tumor cells to evade innate immune surveillance. Unlike antibodies that directly target CD47 and risk binding to red blood cells, anzurstobart’s strategy of targeting SIRPα offers a potentially differentiated safety profile.