CXCL9 and neoplasm: CXCL9 is a critical chemokine that binds CXCR3 on T cells, enhancing recruitment of cytotoxic CD8+ T cells into the tumor (Gorbachev et al., 2007) and promoting the differentiation of inflammatory T helper type 1 (Th1) and Th17 CD4 T cells (Karin et al., 2016).