['carcinoma, non-small-cell lung']
['mk-3475', 'gemcitabine']

        Inclusion Criteria:

          -  Women or men with advanced, histologically proven NSCLC.

          -  Patients must have received at least one but no more than three prior systemic
             therapies for advanced disease.

          -  Any toxicity related to prior therapies that, in the opinion of the investigator,
             would potentially be worsened with anti-PD1 therapy or gemcitabine should be resolved
             to less than Grade 1.

          -  Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1.

          -  Women of childbearing potential must have a negative pregnancy test

          -  Ability to give informed consent and comply with the protocol.

          -  Anticipated survival minimum 3 months.

          -  Prior therapy with investigational agents must have been completed at least 3 weeks
             prior to study enrollment.

          -  Patients must have normal organ and marrow function as seen on protocol-defined blood
             test results

          -  Archived tumor tissue (minimum of 8 slides for paraffin-embedded tumor tissue)
             available

          -  Measurable disease by RECIST 1.1 criteria.

          -  Treated brain metastases will be allowed, provided they are asymptomatic.

          -  Radiation for symptomatic lesions outside the Central nervous system (CNS) must have
             been completed at least 2 weeks prior to study enrollment.

        Exclusion Criteria:

          -  Prior therapy with any anti-PD-1, anti-PD-L1, or anti-CTLA4 antibody.

          -  Prior therapy with gemcitabine.

          -  Prior complications from radiation, such as history of radiation pneumonitis or
             pulmonary edema that, in the opinion of the investigator, may have risk of increasing
             toxicity with anti-PD1 therapy.

          -  Active autoimmune disease except vitiligo or stable hypothyroidism.

          -  Active and ongoing steroid use, except for non-systemically absorbed treatments (such
             as inhaled or topical steroid therapy for asthma, cardiopulmonary disease (COPD),
             allergic rhinitis).

          -  Active other malignancy, except for controlled basal cell skin carcinoma.

          -  HIV positive and/or Hepatitis B or C positive.

          -  Other medical or psychiatric conditions that in the opinion of the Principal
             Investigator would preclude safe participation in this protocol.
      