Inclusion Criteria:

          -  Ability to comply with the study protocol, in the investigator's judgment

          -  Aged 18 years or older

          -  Have previously untreated documented Chronic Lymphocytic Leukemia (CLL) according to
             the International Workshop on Chronic Lymphocytic Leukemia (iwCLL) criteria

          -  CLL requiring treatment according to the iwCLL criteria

          -  Cumulative Illness Rating Scale (CIRS) score ≤ 6 and creatinine clearance (CrCl) ≥ 70
             mL/min

          -  Hematology values within the following limits, unless cytopenia is caused by the
             underlying disease (i.e., no evidence of additional bone marrow (BM) dysfunction;
             e.g., myelodysplastic syndrome, hypoplastic BM):

               -  Absolute neutrophil count ≥ 1.0 x 109/L, unless there is BM involvement

               -  Platelet count ≥ 75 x 109/L and more than 7 days since last transfusion, or ≥ 30
                  x 109/L if there is BM involvement

          -  Adequate liver function as indicated by a total bilirubin, aspartate aminotransferase,
             and Alanine transaminase ≤ 2 times the institutional upper limit of normal (ULN)
             value, unless directly attributable to the participant's CLL

          -  Life expectancy >6 months

          -  For women of childbearing potential: agreement to remain abstinent (refrain from
             heterosexual intercourse) or use contraception and agreement to refrain from donating
             eggs

          -  For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use
             contraceptive methods, and agreement to refrain from donating sperm

        Exclusion Criteria:

          -  Transformation of CLL to aggressive Non-Hodgkin's Lymphoma (NHL)

          -  Participants with Small Lymphocyclic Lymphoma (SLL) only

          -  Known central nervous system involvement

          -  Participants with a history of confirmed progressive multifocal leukoencephalopathy
             (PML)

          -  Detected del(17p) or TP53 mutation (valid test within 6-months from screening is
             required for randomisation)

          -  An individual organ/system impairment score of 4 as assessed by the Cumulative Illness
             Rating Scale (CIRS) definition limiting the ability to receive the treatment regimen
             of this trial with the exception of eyes, ears, nose, throat organ system

          -  Participants with uncontrolled autoimmune hemolytic anemia or immune thrombocytopenia

          -  History of prior malignancy

          -  Participants with infections requiring IV treatment (Grade 3 or 4) within the last 8
             weeks prior to enrollment

          -  Evidence of other clinically significant uncontrolled conditions including but not
             limited to active or uncontrolled systemic infection (e.g., viral, bacterial, or
             fungal)

          -  History of severe allergic or anaphylactic reactions to humanized or murine monoclonal
             antibodies or known sensitivity or allergy to murine products

          -  Hypersensitivity to fludarabine, bendamustine, cyclophosphamide, rituximab,
             obinutuzumab, or venetoclax or to any of the excipients (e.g., trehalose)

          -  Pregnant women and nursing mothers

          -  Vaccination with a live vaccine ≤ 28 days prior to randomization

          -  Prisoners or participants who are institutionalized by regulatory or court order or
             persons who are in dependence to the Sponsor or an investigator

          -  History of illicit drug or alcohol abuse within 12 months prior to screening, in the
             investigator's judgment

          -  Positive test results for chronic hepatitis B virus (HBV) infection (defined as
             positive hepatitis B surface antigen [HBsAg] serology)

          -  Positive test result for hepatitis C (hepatitis C virus [HCV] antibody serology
             testing)

          -  Participants with known infection with HIV or Human T-Cell Leukemia Virus 1 (HTLV-1)

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

          -  Received any of the following agents within 28 days prior to the first dose of study
             treatment:

               -  Immunotherapy

               -  Radiotherapy

               -  Hormone therapy

               -  Any therapies intended for the treatment of lymphoma/leukemia whether approved or
                  experimental

          -  Participants who have received the following agents:

               -  Strong and moderate CYP3A inhibitors/inducers within 7 days prior to the
                  initiation of study treatment

               -  Steroid therapy for anti-neoplastic intent with the exception of inhaled steroids
                  for asthma, topical steroids, or replacement/stress corticosteroids within 7 days
                  prior to the first dose of study drug administration

               -  Consumed grapefruit, grapefruit products, Seville oranges(including marmalade
                  containing Seville oranges), or star fruit within 3 days prior to the first dose
                  of study drug and throughout venetoclax administration

          -  Inability to swallow a large number of tablets.