This is a small open-label pilot clinical trial of semaglutide in adults (age 18 or older, n=8) with obesity (BMI≥30 kg/m2), and chronic advanced lung disease (interstitial lung disease, sarcoidosis, chronic obstructive pulmonary disease, or pulmonary hypertension requiring supplemental oxygen on exertion). This study will evaluate medication adherence and side effects to determine semaglutide tolerability. Markers of physical function and pulmonary function will be evaluated before therapy and after 12 weeks of therapy to determine the effect of semaglutide on function. Measures of fat and muscle, will be performed before therapy and after 12 weeks of therapy to evaluate how semaglutide alters body composition in this population. Study participants will be monitored for 12 weeks while receiving semaglutide therapy.