Indeed several studies have identified tumor properties that have correlated the with outcome of immunotherapies, including the expression of cytokines (interferon-γ), chemokines (CCL5, CXCL9, CXCL10), immunoregulatory molecules such as indolamine-2,3-dioxygenase [8, 19] and, more recently, tumor expression of PD-L1 that was reported to be predictive for responses to checkpoint inhibitors in melanoma [20]. The gene discussed is CXCL9; the disease is neoplasm.