CXCL1 and neoplasm: On the contrary, CXCL5, CXCL1 and CXCL2 have a tumor-promoting effect because they recruit MDSCs, which can play an immunosuppressive role by suppressing the immune function of lymphocytes through the secretion of Arg-1 and iNOS, and CXCL1 and CXCL2 also reduce the number of CD8+ T cells (69–72, 75, 76).