ERBB4 and breast cancer: In our previous MUKDEN 01 study, neoadjuvant pyrotinib (a pan‐HER tyrosine kinase inhibitor [TKI] targeting HER1, HER2, and HER4 that has been approved for the treatment of HER2‐positive early or advanced breast cancer in China)8, 12, 14 plus dalpiciclib (a CDK4/6 inhibitor approved for the treatment of HR‐positive, HER2‐negative advanced breast cancer in China)23, 24 and letrozole showed a tpCR rate of 30.4% and a residual cancer burden (RCB) −0 or −I rate of 55.7% in patients with stage II–III TPBC.25