One of the most notable CXCR1/2 ligands, IL-8 (CXCL8), is a known inducer of tumor cell plasticity, attractant of suppressive myeloid-derived suppressor cells to the tumor, and correlates with failure of treatment in numerous cancer types, including failure to checkpoint inhibitor therapy [28,29,30,31]. This evidence concerns the gene CXCR1 and cancer.