Immune-Marker Platform for Patients With Advanced Lung Cancer

The goal of this observational study is to better understand how the immune system and certain tumor markers are linked to treatment response in patients with advanced non-small cell lung cancer (NSCLC) who receive immunochemotherapy. The investigators aim to answer the following questions: * Can the investigators successfully analyze immune markers and gene activity from small tumor samples (biopsies)? * Are these markers connected to how well patients respond to immunochemotherapy and how their disease progresses? What will participants do? * Provide tumor tissue samples (biopsies) at key points: before treatment, about 6 weeks after starting immunochemotherapy, and if the cancer grows or treatment changes. * Allow their tumor samples to be analyzed in the lab using advanced techniques to measure immune and genetic markers. * Share clinical information (such as treatment response and disease progression) so investigators can study how it relates to these markers. This study does not test a new drug or treatment.