Testing the Addition of a Type of Drug Called Immunotherapy to the Usual Chemotherapy Treatment for Non-small Cell Lung Cancer, an ALCHEMIST Treatment Trial (Chemo-IO [ACCIO])

PRIMARY OBJECTIVE: I. To compare the disease free survival (DFS) between Arm B versus (vs) Arm C in patients with stage IIA-IIIB (T3-4N2) non-small cell lung cancer. SECONDARY OBJECTIVES: I. To compare the overall survival (OS) between the two treatment arms in patients with stage IIA-IIIB (T3-4N2) non-small cell lung cancer. II. To compare the adverse event rates and drug discontinuation rates due to adverse events in patients with stage IIA-IIIB (T3-4N2) non-small cell lung cancer. III. To compare the adverse event (AE) rates for Arms B and C with A (prior to Update #7) and estimate the DFS and OS in Arm A. IV. To compare the DFS and OS in patients with stage IIA-IIIB (T3-4N2) non-small cell lung cancer that receive at least 2 cycles of initial adjuvant chemotherapy. QUALITY OF LIFE OBJECTIVES: I. To compare patient-reported quality of life (QOL) one year after randomization as assessed by the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ)-Core (C)30 between patients randomized to receive adjuvant chemotherapy followed by pembrolizumab (Arm B), and those randomized to receive adjuvant chemotherapy + pembrolizumab concomitantly (Arm C). II. To compare patient-reported QOL at completion of chemotherapy as assessed by the EORTC QLQ-C30 between patients randomized to receive adjuvant chemotherapy followed by pembrolizumab (Arm B) and those randomized to receive adjuvant chemotherapy + pembrolizumab concomitantly (Arm C). III. To present longitudinal trajectories by arm of patient-reported dyspnea and coughing as assessed by the EORTC QLQ-Lung Cancer (LC13). CORRELATIVE SCIENCE OBJECTIVES: I. To compare the DFS and OS in the PD-L1 subgroup of patients with PD-L1 expression status (\>= 1% vs \< 1%). II. To compare the DFS and OS by tumor mutational burden status (high vs. low) in patients with stage IIA-IIIB (T3-4N2) non-small cell lung cancer. OUTLINE: Patients are randomized to 1 of 2 arms. ARM A (CLOSED AS OF UPDATE #7 on 2/1/2022): INITIAL THERAPY: Patients receive 1 of 4 platinum doublet regimens\* based on the treating physician's choice of each cycle. Treatment repeats every 21 days for 4 cycles in the absence of disease progression or unacceptable toxicity. CONTINUANCE THERAPY: Patients then undergo observation. ARM B: INITIAL THERAPY: Patients receive 1 of 4 platinum doublet regimens\* based on the treating physician's choice of each cycle. Treatment repeats every 21 days for 4 cycles in the absence of disease progression or unacceptable toxicity. CONTINUANCE THERAPY: Patients then receive pembrolizumab intravenously (IV) over 25-40 minutes on day 1 of each cycle. Treatment repeats every 21 days for 17 cycles or every 6 weeks for 16 cycles (patients enrolled after 10/14/2020) in the absence of disease progression or unacceptable toxicity. ARM C: INITIAL THERAPY: Patients receive 1 of 4 platinum doublet regimens\* based on the treating physician's choice of each cycle and pembrolizumab IV over 25-40 minutes on day 1 of each cycle or for cycles 1 and 3 (patients enrolled after 10/14/2020). Treatment repeats every 21 days for 4 cycles in the absence of disease progression or unacceptable toxicity. CONTINUANCE THERAPY: Patients then receive pembrolizumab IV over 25-40 minutes on day 1 of each cycle. Treatment repeats every 21 days for 13 cycles or every 6 weeks for 12 cycles (patients enrolled after 10/14/2020) in the absence of disease progression or unacceptable toxicity. Patients also undergo echocardiogram (ECHO) as clinically indicated during screening and on the trial. Patients may undergo magnetic resonance imaging (MRI) during screening and as clinically indicated on the trial, as well as computed tomography (CT) and blood sample collection throughout the trial. \*ACCEPTABLE REGIMENS: DOUBLET I: Patients receive cisplatin IV and pemetrexed IV over 10 minutes on day 1 of each cycle. DOUBLET II: Patients receive carboplatin IV over and pemetrexed IV over 10 minutes on day 1 of each cycle. DOUBLET III: Patients receive cisplatin IV on day 1 of each cycle and gemcitabine hydrochloride IV on days 1 and 8 of each cycle. DOUBLET IV: Patients receive carboplatin IV and paclitaxel IV over 1-96 hours on day 1 of each cycle. After completion of study treatment, patients are followed up at 6 weeks, then every 3 months for 2 years from randomization, every 6 months for years 2-4 from randomization, and then annually for up to 10 years from randomization.