In this video, Frédérique Penault-Llorca, MD, PhD, professor of pathology, University of Clermont-Ferrandand, France, and Aditya Bardia, MD, MPH, director of translational research integration, UCLA, discuss the current and evolving landscape of biomarker testing in HR+/HER2- metastatic breast cancer. They discuss appropriate timing and effective use of both liquid and tumor biopsies, the need to include all relevant biomarkers in test requests throughout the care continuum, and the impact of testing results on both treatment decisions and patient management.