Immune Signature Analysis of Disease Progression in Post Immunotherapy Lung Cancer Patients

Inclusion Criteria 1. Informed consent and HIPAA authorization for release of personal health information signed by the subject. Note: Data from tumor samples, blood samples and radiographic scans prior to enrollment date may be used. 2. Age greater than or equal to18 years at the time of consent. 3. Patients with metastatic non-small cell lung carcinoma have completed first line who, at immunotherapy discontinuation, have completed at least 20 of an anticipated 24 months of immune checkpoint inhibitor monotherapy or pembrolizumab combination chemotherapy in the first line setting. 4. Patients are allowed to continue maintenance chemotherapy. 5. Ability to understand and comply with study procedures for the entire length of the study. 6. Known PD-L1 prior to initiation of first-line treatment for NSCLC. Exclusion Criteria 1. Enrollment/collection of baseline sample earlier than 7 days prior to scheduled last dose of immune checkpoint inhibitor treatment or more than 30 days after last dose of immune checkpoint inhibitor treatment. 2. Patients whose tumors harbor known first line treatment druggable gene abnormalities (e.g. EGFR, BRAF, ALK, ROS1). 3. Patients who have ever received or are currently receiving other types of immunotherapies (nivolumab, ipilimumab, durvalumab or atezolizumab). 4. Known pregnancy. 5. Patients who progress per the enrolling investigator while on treatment with immune checkpoint inhibitor treatment prior to enrollment.