Fit2ThriveMB: Optimization of a Physical Activity Promotion Intervention for Metastatic Breast Cancer Patients

The purpose of this study is to examine which of four components of a digital health intervention using an App and Fitbit meaningfully contribute to increased physical activity in Metastatic Breast Cancer Patients. Participants will be asked to: * Wear a Fitbit and use an app, use 0 to 3 other components for 24 weeks and attend 6 or 12 coaching coaching calls in the first 12 weeks to increase daily steps. * Complete a questionnaire at baseline, week 12 and week 24 * Complete functional performance test (FPT) via Zoom at baseline, week 12 and week 24 * Wear a research activity monitor (Accelerometer) for 7 days at baseline, week 12 and week 24

Inclusion Criteria: * Female sex assigned at birth, age 18 years or older * Diagnosed with metastatic breast cancer or locally advanced disease not amenable to surgical resection. * Self-report engagement in \