A Study to Assess the Safety and Tolerability of Atezolizumab in Combination With Other Immune-Modulating Therapies in Participants With Locally Advanced or Metastatic Solid Tumors

Inclusion Criteria:

- Histologically or cytologically documented locally advanced or metastatic solid tumors
meeting the following study drug-specific criteria:

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

- Life expectancy greater than or equal to (>/=) 12 weeks

- Measurable disease, as defined by RECIST v1.1

- Adequate hematologic and end organ function as confirmed by laboratory results within
14 days prior to the first study treatment

Inclusion criteria specific to Arm A: Atezolizumab+ Ipilimumab

- Escalation stage: NSCLC participants

- Mandatory biopsy cohort: NSCLC or melanoma atezolizumab

- Prior atezolizumab-treated cohort: participants with NSCLC or melanoma previously
treated with atezolizumab

Inclusion criteria specific to Arm B: Atezolizumab+ Interferon alfa-2b

- Escalation stage: RCC or melanoma participants

- Expansion stage: RCC or melanoma participants

- Mandatory biopsy cohort: RCC or melanoma participants

- Prior immunotherapy-treated cohort: participants with RCC, NSCLC, or melanoma
previously treated with programmed death-ligand 1 (PD-L1)/ Programmed death 1 (PD-1)

Inclusion Criteria Specific to Arm C (Atezolizumab plus PEG-Interferon Alafa-2a):

- Cohort 1: participants with RCC

Inclusion Criteria Specific to Arm D (Atezolizumab plus PEG−Interferon Alfa-2a
+Bevacizumab)

- Cohort 1: participants with metastatic RCC with no prior line of systemic therapy for
metastatic disease

- Cohorts 2-3: disease progression during or after at least one previous systemic,
anti-cancer treatment for locally advanced or metastatic non-squamous solid tumors;
participants with sensitizing epidermal growth factor receptor (EGFR) mutations or
anaplastic lymphoma kinase (ALK) rearrangements must have failed or are intolerant to
prior treatment with EGFR or ALK inhibitors; participants with melanoma with
actionable BRAF mutations (e.g., V600) must have failed or are intolerant to prior
treatment with BRAF inhibitors

Inclusion Criteria Specific to Arm E (Atezolizumab +Obinutuzumab)

- R/M HNSCC participants with at least one prior line of systemic therapy

Inclusion Criteria Specific to prior Anti−PD-L1/PD-1 Treated Cohorts:

- No permanent discontinuation of atezolizumab or other immunotherapies due to a
treatment-related adverse event

- Recovery from all immunotherapy-related adverse events to Grade less than or equal to
(≤) 1 or baseline at the time of consent

Exclusion Criteria:

General Medical Exclusions:

- Pregnant and lactating women

- Any approved anti-cancer therapy, including chemotherapy or hormonal therapy, within 3
weeks prior to initiation of study treatment, with the following exception: (1)
hormone-replacement therapy or oral contraceptives; (2) tyrosine kinase inhibitors
(TKIs) that have been discontinued greater than (>) 7 days prior to Cycle 1, Day 1,
baseline scans must be obtained after discontinuation of prior TKIs

- Investigational therapy within 28 days prior to initiation of study treatment

- History of severe allergic, anaphylactic, or other hypersensitivity reactions to
chimeric or humanized antibodies or fusion proteins

- Known hypersensitivity or allergy to Chinese hamster ovary cell products or any
component of the atezolizumab formulation

- History of or active autoimmune disease

- History of idiopathic pulmonary fibrosis (including pneumonitis), drug-induced
pneumonitis, organizing pneumonia, risk of pulmonary toxicity, or evidence of active
pneumonitis on screening chest computed tomography (CT) scan

- Prior allogeneic bone marrow transplantation or prior solid organ transplantation

- History of human immunodeficiency virus (HIV)

- Participants with active hepatitis B

- Participants with active hepatitis C

- Participants with active tuberculosis

- Participants with a history of confirmed progressive multifocal leukoencephalopathy

- Any serious medical condition, physical examination finding, or abnormality in
clinical laboratory tests that, in the investigator's judgment, precludes the
participant's safe participation in and completion of the study

Cancer-Specific Exclusions:

- Active or untreated central nervous system (CNS) metastases, as determined by CT or
magnetic resonance imaging (MRI) evaluation during screening and prior radiographic
assessments

- Spinal cord compression not definitively treated with surgery and/or radiation or
previously diagnosed and treated spinal cord compression without evidence that disease
has been clinically stable for >/= 2 weeks prior to screening

- Leptomeningeal disease

- Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent
drainage procedures (once monthly or more frequently); participants with indwelling
catheters are allowed.

- Uncontrolled tumor-related pain

- Uncontrolled hypercalcemia or symptomatic hypercalcemia requiring continued use of
bisphosphonate therapy or denosumab

- History of other malignancy within 2 years prior to screening, except for
appropriately treated carcinoma in situ of the cervix, non-melanoma skin carcinoma,
Stage I uterine cancer, localized prostate cancer treated with curative intent, ductal
carcinoma in situ treated surgically with curative intent, or other cancers with a
similar outcome

Exclusion Criteria Related to Medications:

- Prior treatment with cluster of differentiation 137 (CD137) agonists or immune
checkpoint blockade therapies (Note: Participants enrolled in the prior
anti−PD-L1/PD-1 treated cohorts with melanoma may have received prior anti-cytotoxic
T-lymphocyte-associated protein 4 treatment or other immunotherapies)

- Treatment with systemic immunostimulatory agents within four weeks or five half-lives
of the drug, whichever is shorter, prior to Cycle 1, Day 1

- Treatment with systemic immunosuppressive medications within 2 weeks prior to Cycle 1,
Day 1 (the use of inhaled corticosteroids and mineralocorticoids is allowed)

Exclusion Criteria Specific to Interferon Alpha Therapy (Arms B−D):

- History of depression, suicidal ideation or behavior, bipolar disorder, or psychosis

- Hypersensitivity to interferon alpha or any component of the product

Exclusion Criteria Specific to Bevacizumab (Arm D)

- Inadequately controlled hypertension

- Prior history of hypertensive crisis or hypertensive encephalopathy

- Significant vascular disease within 6 months prior to Day 1

- History of hemoptysis

- Evidence of bleeding diathesis or significant coagulopathy (in the absence of
therapeutic anticoagulation)

- History of tracheoesophageal fistula, gastrointestinal perforation, or intra-abdominal
abscess within 6 months prior to Day 1

- Clinical signs or symptoms of gastrointestinal obstruction or requirement for routine
parenteral hydration, parenteral nutrition, or tube feeding

- Evidence of abdominal free air that is not explained by paracentesis or recent
surgical procedure

- Proteinuria, as demonstrated by urine dipstick or > 1.0 gram of protein in a 24-hour
urine collection

- Metastatic disease that involves major airways or blood vessels, or centrally located
mediastinal tumor masses of large volume

Exclusion Criteria Specific Obinutuzumab (Arm E)

- Hypersensitivity to obinutuzumab

- Prior treatment with obinutuzumab