CXCL12 and neoplasm: In triple-negative breast cancer (TNBC), CAFs recruit monocytes to the tumor site through the CXCL12/CXCR4 axis and facilitate the progression of monocytes to immunosuppressive stabilin 1 (STAB1)+ lipid-associated macrophages, which are related to resistance to PD-1 blockade (60).