Inclusion Criteria:

          -  Histologically proven stage I NSCLC =< 5 cm diameter

          -  One or more high-risk features identified:

               -  Tumor diameter >= 2 cm

               -  Tumor standardized uptake value maximum (SUVmax) >= 6.2

               -  Moderately, poorly differentiated or undifferentiated histology

          -  Evaluable disease per RECIST 1.1

          -  Patients must be medically or surgically inoperable as determined by a physician OR
             unwilling to undergo surgical resection

          -  All patients must have an forced expiratory volume in 1 second (FEV1) >= 700cc

          -  All patients must have a carbon monoxide diffusing capability test (DLCO) >= 5.5
             m/min/mmHg

          -  Eastern Cooperative Oncology Group (ECOG) performance status score of 0-2

          -  Life expectancy >= 12 months

          -  Absolute neutrophil count (ANC) > 1500 cells/uL

          -  White blood cell count (WBC) > 2500/uL

          -  Lymphocyte count > 500/uL

          -  Platelet count > 100,000/uL

          -  Hemoglobin > 9 g/dL

          -  Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) < 2.5 x upper
             limit of normal (ULN) with alkaline phosphatase =< 2.5 x ULN OR AST and ALT =< 1.5 x
             ULN, with alkaline phosphatase > 2.5 x ULN

          -  Serum bilirubin =< 1.0 x ULN

          -  International normalized ratio (INR) and activated partial thromboplastin time (aPTT)
             < 1.5 x ULN (for patients on anticoagulation they must be receiving a stable dose for
             at least 1 week prior to enrollment)

          -  Creatinine clearance > 30 mL/min by Cockcroft-Gault formula

          -  No history of severe hypersensitivity reactions to other monoclonal antibodies (mAbs)

          -  No other active malignancy

          -  Patients with a history of autoimmune-related hypothyroidism on a stable dose of
             thyroid replacement hormone are eligible

          -  Patients with controlled type 1 diabetes mellitus on a stable insulin regimen are
             eligible

          -  Archival tumor sample available; tissue from an fine-needle aspiration (FNA) is
             allowed but tumor tissue from a core needle biopsy is preferred

          -  For female patients of childbearing potential and male patients with partners of
             childbearing potential agreement (by patient and/or partner) to use highly effective
             form(s) of contraception (i.e., one that results in a low failure rate [< 1% per year]
             when used consistently and correctly) and to continue its use for 6 months after the
             last dose of MPDL3280A

          -  Signed informed consent

          -  Ability to comply with the protocol

        Exclusion Criteria:

          -  Uncontrolled concomitant disease

          -  Significant cardiovascular disease (New York Heart Association Class [NYHA] class II
             or greater); myocardial infarction within 3 month prior to randomization, unstable
             arrhythmias, unstable angina or a patient with a known left ventricular ejection
             fraction (LVEF) < 40%

          -  Severe infection within 4 weeks prior to enrollment

          -  Active tuberculosis

          -  Oral or IV antibiotics within 2 weeks or 5 half-lives prior to enrollment

          -  History of autoimmune disease

          -  Positive for human immunodeficiency virus (HIV), hepatitis B (hepatitis B surface
             antigen [HBsAg] reactive), or hepatitis C virus (hepatitis C virus ribonucleic acid
             [HCV RNA] [qualitative] is detected)

          -  History of idiopathic pulmonary fibrosis, drug-induced pneumonitis, organizing
             pneumonia

          -  Treatment with systemic immunostimulatory agents within 4 weeks or five half-lives of
             the drug, whichever is shorter, prior to enrollment

          -  Treatment with systemic corticosteroids or other systemic immunosuppressive
             medications within past 4 weeks or 5 half-lives whichever is shorter

          -  Pregnant and/or lactating women