This mouse strain is generated through genetic engineering, where the coding region of the endogenous mouse Sirpa gene is replaced with the corresponding human SIRPα gene sequence. This model expresses the human SIRPα protein precisely within an immunocompetent mouse. SIRPα is an immunoregulatory receptor primarily expressed on the surface of myeloid cells (e.g., macrophages, dendritic cells). Its interaction with the CD47 ligand, widely present on normal and tumor cell surfaces, delivers a "don't eat me" signal that inhibits macrophage phagocytosis, making it a key pathway for tumor immune evasion. This model enables the functional, efficacy, and safety evaluation of therapies targeting human SIRPα (such as SIRPα-Fc fusion proteins, antagonistic antibodies) in an in vivo system, making it a core preclinical research tool for developing macrophage checkpoint therapies and enhancing anti-tumor immune responses.