Moreover, the landscape of targeted therapies for breast cancer is rapidly evolving, with the introduction of innovative options, including anti-HER2-ADCs, anti-HER2-TKIs, endocrine therapies, CDK4/6 inhibitors, PI3K inhibitors, and immune checkpoint inhibitors (ICIs).22,36–39 The continuous development of novel drugs and combinational regimens has challenged existing efficacy prediction models, underscoring the need to optimize treatment strategies. This evidence concerns the gene CDK4 and breast cancer.