We used a gene signature that contains four genes (i.e., IFNγ, CD274, LAG3, and CXCL9; IFNγ+ signature), previously used to stratify urothelial and non-small-cell lung carcinoma cancer patient response to anti-PD-L1 durvalumab treatment to evaluate the immune-high and immune-low tumors.[6] When evaluating HR + HER2- and TN breast cancer, the mean of the IFNγ+ signature score was higher in TN than HR+ HER2− (0.08 vs. −0.047; Welch’s 2 sided T-test P-value =5.9×10− 13), but the ranges of the scores were overlapping (TN: [−0.32, 0.41]; HR+: [−0.37, 0.32]). This evidence concerns the gene CXCL9 and breast cancer.