Results from the adaptively randomized I-SPY2 study suggest that anti-PD-(L)1 agents have the potential to increase the proportion of patients with high-risk ER+/HER2− BC who achieve pCR or minimal residual disease (residual cancer burden (RCB) score of 0 or I) following neoadjuvant treatment10,17. Here, ESR1 is linked to breast cancer.