A Study Comparing Zanubrutinib With Bendamustine Plus Rituximab in Participants With Previously Untreated CLL or SLL

Key Inclusion Criteria: * Unsuitable for chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab (FCR) * Confirmed diagnosis of CD20-positive CLL or SLL, requiring treatment * Measurable disease by imaging * Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1 or 2 * Life expectancy ≥ 6 months * Adequate bone marrow function * Adequate renal and hepatic function Key Exclusion Criteria: * Previous systemic treatment for CLL/SLL * Requires ongoing need for corticosteroid treatment * Known prolymphocytic leukemia or history of or suspected Richter's transformation. * Clinically significant cardiovascular disease * Prior malignancy within the past 3 years, except for curatively treated basal or squamous cell skin cancer, non-muscle-invasive bladder cancer, carcinoma in situ of the cervix of breast, or localized Gleason score 6 prostate cancer * History of severe bleeding disorder * History of stroke or intracranial hemorrhage within 6 months before the first dose of study drug * Severe or debilitating pulmonary disease * Inability to swallow capsules or disease affecting gastrointestinal function * Active infection requiring systemic treatment * Known central nervous system involvement by leukemia or lymphoma * Underlying medical condition that will render the administration of study drug hazardous or obscure interpretation of toxicity or AEs * Known infection with human immunodeficiency virus (HIV) or active hepatitis B or C infection * Major surgery ≤ 4 weeks prior to start of study treatment * Pregnant or nursing females * Vaccination with live vaccine within 35 days prior to the first dose of study drug. * Ongoing alcohol or drug addiction * Known hypersensitivity to zanubrutinib, bendamustine, rituximab, or venetoclax (as applicable) or any other ingredients of the study drugs * Requires ongoing treatment with strong cytochrome P450 (CYP3A) inhibitor or inducer * Concurrent participation in another therapeutic clinical study NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.