Initial phase I (KEYNOTE-028) [171] and phase II (KEYNOTE-086) [172] with pembrolizumab monotherapy demonstrated durable response in naïve PD-L1 positive and a subset of previously treated metastatic TNBC [172], as well as modest response in hormone positive/HER2 negative breast cancers [171]. This evidence concerns the gene ERBB2 and breast cancer.