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

This study uses PET/CT scans to monitor how well treatment is working in patients with advanced non-small cell lung cancer (NSCLC) who are receiving both chemotherapy and immunotherapy, followed by radiation. PET/CT scans show metabolic activity in cancer cells, and researchers want to see how these scan results change during treatment and whether they can predict outcomes. **You may be eligible if...** - You have stage IV non-small cell lung cancer confirmed by biopsy - You have not yet received chemotherapy or immunotherapy for your advanced disease - You are planning to receive a platinum-based chemotherapy plus an immunotherapy drug (PD-1 or PD-L1 inhibitor) - Your cancer is measurable on imaging **You may NOT be eligible if...** - You previously received chemotherapy or immunotherapy for advanced lung cancer - You progressed within 6 months of completing earlier adjuvant chemotherapy Talk to your doctor to see if this trial is right for you.