CXCR2 and neoplasm: Recruited C-X-C motif chemokine receptor 2 (CXCR2)-expressing MDSCs in the tumor microenvironment, driven by the C-X-C motif chemokine ligand (CXCL)1/2/5 expressed in liver tumor cells, can also suppress IFN-γ secretion in NKT cells through membrane-bound TGF-β [20].