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 trial.

        NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.