At the same time, KATE2 (NCT02924883) assessed the effectiveness and safety of T‐DM1 plus atezolizumab in locally advanced or metastatic HER2‐positive breast cancer patients previously managed with trastuzumab and taxane‐based therapies, the results indicated that the addition of atezolizumab to the T‐DM1 regimen did not yield a significant PFS benefit in the intention‐to‐treat (ITT) population. This evidence concerns the gene ERBB2 and breast cancer.