Pembrolizumab After Radiation Therapy in Treating Patients With Pleural Malignant Mesothelioma

Inclusion Criteria: * Patients must have a histologic diagnosis of malignant pleural mesothelioma, with histologic diagnosis from the pleura or relevant lymph node stations, including mediastinal, hilar, or supraclavicular lymph nodes * Be willing and able to provide written informed consent/assent for the trial * Have measurable or non-measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1; however, note that patients in Cohort 1 that have undergone an R0 resection will be eligible for the trial * Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG) performance scale * Absolute neutrophil count (ANC) \>=1,500 /mcL (within 10-15 days of treatment initiation) * Platelets \>= 100,000 /mcL (within 10-15 days of treatment initiation) * Hemoglobin \>= 9 g/dL or \>= 5.6 mmol/L without transfusion or erythropoietin (EPO) dependency (within 7 days of assessment) (within 10-15 days of treatment initiation) * Serum creatinine =\< 1.5 X upper limit of normal (ULN) or measured or calculated creatinine clearance (glomerular filtration rate \[GFR\] can also be used in place of creatinine or creatinine clearance \[CrCl\]) \>= 60 mL/min for subject with creatinine levels \> 1.5 X institutional ULN (within 10-15 days of treatment initiation) * Serum total bilirubin =\< 1.5 X ULN or direct bilirubin =\< ULN for subjects with total bilirubin levels \> 1.5 ULN (within 10-15 days of treatment initiation) * Aspartate aminotransferase (AST)…