Inclusion Criteria:

          1. Eastern Cooperative Oncology Group (ECOG) Performance Status score of 0 - 1 (Appendix
             A).

          2. Adequate hematologic function defined as:

             - Absolute neutrophil count (ANC) ≥1500/μL

               -  Hemoglobin (Hgb) ≥9 g/dL

               -  Platelets ≥100,000/µL

          3. Adequate liver function defined as:

               -  Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤2.5 x the
                  upper limit of normal (ULN)

               -  Total bilirubin ≤1.5 x ULN (Patients with known Gilbert disease: serum bilirubin
                  level ≤ 3 x ULN)

          4. Adequate renal function defined as serum creatinine ≤1.5 mg/dL (133 μmol/L) OR
             calculated creatinine clearance ≥50 mL/min as calculated by Cockcroft and Gault
             Formula (for the solid tumor cohort receiving atezolizumab monotherapy, the threshold
             can be reduced to a creatinine clearance of ≥30 mL/min.).

          5. Male patients with female partners of childbearing potential and female patients of
             childbearing potential are required to use two forms of acceptable contraception,
             including one barrier method, during their participation in the study and for 5 months
             following last dose of study drug(s). Male patients must also refrain from donating
             sperm during their participation in the study (Appendix C).

          6. Age ≥18 years.

          7. Willingness to provide a new pre-treatment tumor biopsy.

          8. Willingness and ability to comply with study and follow-up procedures.

          9. Ability to understand the nature of this study and give written informed consent.

        Inclusion Arm A - Non-small cell lung cancer 1. Advanced squamous or non-squamous NSCLC 2.
        Disease progression after first-line anti-PD-1 therapy (pembrolizumab) for ≥4 months
        Inclusion Arm B - Advanced solid tumors

          1. Patients with advanced RCC, TNBC, SCLC, SCCHN, melanoma, MSI-high solid tumors, and
             patients with NSCLC who were treated with PD-1 in the ≥ second-line setting, or NSCLC
             patients who progressed after pembrolizumab plus chemotherapy in the first-line
             setting Additional cohorts may be added.

          2. MSI-high solid tumors as defined by local testing for MSI/MMR will be included.

          3. Previously received and tolerated nivolumab or pembrolizumab therapy (and was the last
             therapy prior to enrollment).

          4. Evidence of disease progression.

        Exclusion Criteria:

          1. History of severe allergic anaphylactic reactions to chimeric or humanized antibodies
             or fusion proteins

          2. History of any Grade 3 or 4 toxicities to a prior CPI treatment

          3. Known hypersensitivity to Chinese hamster ovary cell products or to any component of
             the atezolizumab formulation

          4. Most recent immunotherapy ≤21 days and ≥ Grade 1 immunotherapy-related side effects,
             with the exception of alopecia.

          5. Use of systemic immunostimulatory agents (including, but not limited to, interferon
             and interleukin 2 [IL-2]) ≤28 days or 5 half-lives (whichever is longer) prior to the
             first dose of atezolizumab.

          6. Treatment with systemic immunosuppressive medication (including, but not limited to,
             corticosteroids, cyclophosphamide, azathioprine, methotrexate, thalidomide, and
             anti-TNF- agents) within 2 weeks prior to initiation of study treatment, or
             anticipation of need for systemic immunosuppressive medication during the course of
             the study, with the following exceptions:

               -  Patients who received acute, low-dose systemic immunosuppressant medication or a
                  one-time pulse dose of systemic immunosuppressant medication (e.g., 48 hours of
                  corticosteroids for a contrast allergy) are eligible for the study.

               -  Patients who received mineralocorticoids (e.g., fludrocortisone), inhaled
                  corticosteroids for chronic obstructive pulmonary disease (COPD) or asthma, or
                  low-dose corticosteroids for orthostatic hypotension or adrenal insufficiency are
                  eligible for the study.

          7. Treatment with a live, attenuated vaccine within 4 weeks prior to initiation of study
             treatment, or anticipation of need for such a vaccine during the course of the study
             or within 5 months after the last dose of atezolizumab

          8. Treatment with therapeutic oral or IV antibiotics within 2 weeks prior to initiation
             of study treatment.

             • Patients receiving prophylactic antibiotics (e.g., to prevent a urinary tract
             infection or chronic obstructive pulmonary disease exacerbation) are eligible for the
             study.

          9. Requirement for use of denosumab during the study. Patients who are receiving
             denosumab for any reason (including hypercalcemia) must be willing and eligible to
             receive a bisphosphonate instead while in the study.

         10. Wide field radiotherapy (including therapeutic radioisotopes such as strontium 89)
             administered ≤28 days or limited field radiation for palliation ≤7 days prior to
             starting study drug or has not recovered from side effects of such therapy.

         11. Major surgical procedures ≤28 days of beginning study drug, or minor surgical
             procedures ≤7 days. No waiting required following port-a-cath placement.

         12. Symptomatic, untreated, or actively progressing CNS metastases. Patients who have
             received radiation or surgery for brain metastases are eligible if therapy was
             completed at least 2 weeks prior to study entry and there is no evidence of central
             nervous system disease progression, mild neurologic symptoms, and no requirement for
             chronic corticosteroid therapy. Anticonvulsant therapy at a stable dose is permitted.

         13. Prior allogeneic stem cell or solid organ transplantation

         14. Pregnant or lactating

         15. History of idiopathic pulmonary fibrosis, organizing pneumonia (e.g., bronchiolitis
             obliterans), drug-induced pneumonitis, or idiopathic pneumonitis, or evidence of
             active pneumonitis on screening chest computed tomography (CT) scan

             • History of radiation pneumonitis in the radiation field (fibrosis) is permitted.

         16. Uncontrolled diabetes mellitus. Patients with Type II diabetes are eligible if they
             require only oral hypoglycemic agents and fasting blood glucose level is ≤120.
             Patients with Type I diabetes are eligible if HbAlc is ≤7%.

         17. Significant cardiovascular disease, such as New York Heart Association Class II or
             greater cardiac disease, myocardial infarction, or cerebrovascular accident within 3
             months prior to initiation of study treatment, unstable arrhythmia, or unstable angina
             (see Appendix B)

         18. History of leptomeningeal disease

         19. Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent
             drainage procedures (once monthly or more frequently)

             • Patients with indwelling catheters (e.g., PleurX) are allowed.

         20. Uncontrolled or symptomatic hypercalcemia (-1.5 mmol/L ionized calcium or calcium -12
             mg/dL or corrected serum calcium -ULN).

         21. Active or history of autoimmune disease or immune deficiency, including, but not
             limited to, myasthenia gravis, myositis, autoimmune hepatitis, systemic lupus
             erythematosus, rheumatoid arthritis, inflammatory bowel disease, antiphospholipid
             antibody syndrome, Wegener granulomatosis, Sjögren's syndrome, Guillain-Barré
             syndrome, or multiple sclerosis (see Appendix F for a more comprehensive list of
             autoimmune diseases and immune deficiencies), with the following exceptions:

             • Patients with a history of autoimmune-related hypothyroidism who are on
             thyroid-replacement hormone are eligible for the study.

             • Patients with eczema, psoriasis, lichen simplex chronicus, or vitiligo with
             dermatologic manifestations only (e.g., patients with psoriatic arthritis are
             excluded) are eligible for the study provided all of following conditions are met:

             - Rash must cover ˂ 10% of body surface area

               -  Disease is well controlled at baseline and requires only low-potency topical
                  corticosteroids

               -  No occurrence of acute exacerbations of the underlying condition requiring
                  psoralen plus ultraviolet A radiation, methotrexate, retinoids, biologic agents,
                  oral calcineurin inhibitors, or high potency or oral corticosteroids within the
                  previous 12 months

         22. Serious active infection within 4 weeks of treatment (including but not limited to
             hospitalization for complications of infection, bacteremia, or severe pneumonia), or
             another serious underlying medical condition that would impair the ability of the
             patient to receive protocol treatment.

         23. Diagnosis of human immunodeficiency virus, hepatitis B, or hepatitis C.

         24. Active tuberculosis

         25. Any other disease, metabolic dysfunction, physical examination finding, or clinical
             laboratory finding that contraindicates the use of an investigational drug, may affect
             the interpretation of the results, or may render the patient at high risk from
             treatment complications

         26. Has a second primary malignancy that in the judgment of the investigator and sponsor
             may affect the interpretation of results.

         27. Psychological, familial, sociological, or geographical conditions that do not permit
             compliance with the protocol.

        Exclusion Arm A - Non-small cell lung cancer

        1. Intervening treatment with a regimen other than CPI prior to enrollment in this study.