LILRB1 and neoplasm: In addition to CD47, the macrophage surface leukocyte immunoglobulin-like receptor B1(LILRB1) protein can specifically recognize major histocompatibility complex I(MHC I) and microglobulin-like β2 (β2M) on the surface of tumor cells, allowing tumor cells to directly escape macrophage phagocytosis (67).