Cyclin-dependent kinase 4/6 (CDK 4/6) inhibitors have emerged as a significant advancement in the treatment of HR+/HER2- metastatic breast cancer (MBC). Despite the clinical efficacy of CDK 4/6 inhibitors in HR+/HER2- metastatic breast cancer, there remains a significant gap in understanding their cost-effectiveness, particularly regarding the long-term economic impact and the key drivers of costs, when used in combination with endocrine therapy. This study aims to systematically review and conduct a meta-analysis of cost-effectiveness studies evaluating CDK4/6 inhibitors in treatment of HR+/HER2- advanced breast cancer and identify key drivers of costs of CDK4/6 inhibitors in combination with endocrine therapy.