CXCR2 and melanoma: More significant therapeutic effects were observed in B16 melanoma bearing mice treated with three-drug combination of hydroquinone (Hy), CXCR2 inhibitor (SB225002, CXCR2i) 49, 50, 52 and PD1 mAb, as manifested by the prolonged survival time and reduced tumor burden in the lung and brain (Figure 7G-K).