PET/CT Changes During Chemoimmunotherapy and Radiation Therapy in Patients With Stage IV Non-small Cell Lung Cancer

Patients undergo PET/CT scan within 4 weeks before starting standard of care chemoimmunotherapy and a second PET/CT scan within 5 days of the second chemoimmunotherapy cycle. Patients receiving standard of care radiation treatment undergo additional PET/CT scans within 4 weeks prior to radiation treatment and 1 month post-radiation treatment. Additionally, patients undergo blood sample collection on study. Patients may also undergo magnetic resonance imaging (MRI) as clinically indicated throughout the study.