Molecular Imaging of FAP Expressing Cancer-associated Fibroblasts in NSCLC Treated With Immune-checkpoint Inhibitors

This imaging study is using a special PET scan tracer that targets a protein called FAP — found on cancer-associated fibroblasts (support cells that help tumors grow) — to better understand how these cells behave in non-small cell lung cancer (NSCLC) during treatment with immune checkpoint inhibitors (immunotherapy). **You may be eligible if...** - You are 18 or older - You have confirmed non-small cell lung cancer (NSCLC) - You are planned to receive immunotherapy (anti-PD-1 or PD-L1) with or without chemotherapy or anti-CTLA4 for advanced disease - Your general health is adequate (ECOG ≤ 2) **You may NOT be eligible if...** - You had surgery or radiation to your chest in the past 8 weeks - Your tumor has EGFR, ALK, or ROS1 mutations (which are typically treated differently) - You are pregnant or breastfeeding - You have had another cancer diagnosis within the last 2 years (with minor exceptions) - You have a significant medical condition the investigator believes could interfere with the study Talk to your doctor to see if this trial is right for you.