CXCL9 and lung cancer: Clinically, there is evidence that high pretreatment CXCL9 and CXCL10 levels are correlated with response to anti–PD-(L)1 therapy in patients with non–small-cell lung cancer [23], and CXCL9 and CXCL10 increase in the first few months of treatment in patients with melanoma responding to PD-1 inhibitor therapy [22].