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

Inclusion Criteria: * Histologically-confirmed or cytologically-confirmed metastatic NSCLC in patients who have not received chemotherapy or immunotherapy for their advanced disease (stage IV or recurrent, using the American Joint Committee on Cancer \[AJCC\]/Union for International Cancer Control \[UICC\] 8th edition for staging) * Evidence of stage IV disease on imaging by CT, PET/CT, or magnetic resonance imaging (MRI) * Plan to treat with a platinum doublet with a PD1 or PDL1 inhibitor * Adjuvant chemotherapy or concurrent chemoradiation for early stage disease does not count as prior therapy unless subject progressed within 6 months of completion of regimen. * Measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) version (v)1.1, at treating physician's discretion * Subjects must be ≥ 18 years of age * Patients with known activating mutations in EGFR, BRAF or known translocation in ALK or ROS-1 are eligible provided they have progressed on or were intolerant to Food and Drug Administration (FDA) approved targeted therapy * Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0-2 * Creatinine =\< 2 mg/dL or creatinine clearance \> 50 mL/min * Aspartate aminotransferase (AST) (serum glutamic-oxaloacetic transaminase \[SGOT\])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase \[SGPT\]) =\< 5x institutional upper limit of normal * Total bilirubin =\< 1.5 mg/dL * Absolute neutrophil count (ANC) \>= 1.5 x 10\^9/L (\>= 150…