Clinical studies have analyzed the efficacy of the PD-L1 antagonist pembrolizumab in ER+/Her2- advanced breast cancer patients, with an ORR of 12% (95% confidence interval (CI), 2.5–31.2%) and clinical benefit rate (CBR) of 20% (95% CI, 7–41%) (155). Here, ERBB2 is linked to breast carcinoma.