SOLAR‐1 trial17 showed great improvements in prolonging progression‐free survival (PFS) and overall survival (OS) with the addition of PI3Kα‐specific inhibitor BYL719 in mutated‐PI3Kα, HR+, HER2‐negative (HER2–) advanced breast cancer who have received endocrine therapy previously. Here, ERBB2 is linked to breast cancer.