In KEYNOTE-522, addition of pembrolizumab to chemotherapy not only increased pCR rates in TN patients, but also improved event-free survival among TN patients with moderate residual disease (residual cancer burden [RCB]-2).42 The extent to which this might be true for HR+HER2– patients and whether it is a result of a downward shift of RCB during neoadjuvant IO or the result of adjuvant IO remains to be seen. The gene discussed is ERBB2; the disease is cancer.