Furthermore, immune cell infiltration16–18, expression of immune genes such as IFNG, CXCL9 and CXCL1016,19, TGF-β signaling20, composition of the tumor microenvironment21, alterations in DNA damage repair (DDR) genes22, abundance of circulating tumor DNA23,24 and the diversity of the T cell receptor (TCR) repertoire16,25,26 have all been associated with response and resistance to ICIs. The gene discussed is CXCL9; the disease is neoplasm.