Furthermore, the IFNγ-induced PD-L1 upregulation which was traditionally considered a major player driving pro-tumoral effects of IFNγ, could potentially now represent the basis for powerful combinatorial approaches with ICBs, a phenomenon similar to the positive predictive value of an otherwise negative prognostic biomarker, HER2/neu amplification, in breast cancer. This evidence concerns the gene IFNG and breast cancer.