A machine learning (ML) model incorporating both clinical and genomic factors outperformed models based solely on either clinical or genomic data in predicting which patients with hormone receptor (HR)-positive, HER2-negative metastatic breast cancer would have better outcomes from adding CDK4/6 inhibitors to endocrine therapy as first-line treatment, according to results presented at the San Antonio Breast Cancer Symposium (SABCS), held December 10-13, 2024.