Pembrolizumab and Concurrent Chemoradiotherapy or Radiation Therapy in Treating Patients With Small Cell Lung Cancer

Is currently participating in or has participated in a study of an investigational agent (except glutamine) or using an investigational device within 2 weeks of the first dose of treatment

Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of trial treatment; with the exception of physiologic steroid replacement

Has had a prior monoclonal antibody within 2 weeks prior to study day 1 or who has not recovered (i.e., =\< grade 1 or at baseline) from adverse events due to agents administered more than 4 weeks earlier

Has had prior chemotherapy, targeted small molecule therapy, within 2 weeks prior to study day 1 or who has not recovered (i.e., =\< grade 1 or at baseline) from adverse events due to a previously administered agent; prior radiation does not require a washout period; note: subjects with =\< grade 2 neuropathy are an exception to this criterion and may qualify for the study; note: if subject received major surgery, they must have recovered adequately from the toxicity and/or complications from the intervention prior to starting therapy

Has a known additional malignancy that is progressing or requires active treatment; exceptions include skin basal cell carcinoma (basal cell carcinoma of the skin), skin squamous cell carcinoma (squamous cell carcinoma of the skin), or in situ cervical cancer that has undergone potentially curative therapy

Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis; subjects with previously treated brain metastases may participate provided they are stable (without evidence of progression by imaging for at least four weeks prior to the first dose of trial treatment and any neurologic symptoms have returned to baseline), have no evidence of new or enlarging brain metastases, and are not using steroids for at least 7 days prior to trial treatment

Has an active autoimmune disease requiring systemic treatment within the past 3 months or a documented history of clinically severe autoimmune disease, or a syndrome that requires systemic steroids or immunosuppressive agents; subjects with vitiligo or resolved childhood asthma/atopy would be an exception to this rule; subjects that require intermittent use of bronchodilators or local steroid injections would not be excluded from the study; subjects with hypothyroidism stable on hormone replacement or Sjogren's syndrome will not be excluded from the study

Has evidence of interstitial lung disease or active, non-infectious pneumonitis

Has an active infection requiring systemic therapy

Has a history or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the trial, interfere with the subject's participation for the full duration of the trial, or is not in the best interest of the subject to participate, in the opinion of the treating investigator

Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial

Is pregnant or breastfeeding, or expecting to conceive or father children within the projected duration of the trial, starting with the pre-screening or screening visit through 120 days after the last dose of trial treatment

Has received prior therapy with an anti-programmed cell death-1 (PD-1), anti-programmed cell death-ligand 1 (PD-L1), anti-programmed cell death 1 ligand 2 (PD-L2), anti-cluster of differentiation (CD)137

Has a known history of human immunodeficiency virus (HIV) (HIV 1/2 antibodies)

Has known active hepatitis B (e.g., hepatitis B surface antigen \[HBsAg\] reactive) or hepatitis C (e.g., hepatitis C virus ribonucleic acid \[HCV RNA\] \[qualitative\] is detected)

Has received a live vaccine within 30 days prior to the first dose of trial treatment

What this study is about