A Study of the Combination of Ibrutinib Plus Venetoclax Versus Chlorambucil Plus Obinutuzumab for the First-line Treatment of Participants With Chronic Lymphocytic Leukemia (CLL)/Small Lymphocytic Lymphoma (SLL)

Prior treatment

• Prior anti-leukemic therapy for CLL or SLL
• Major surgery within 4 weeks of first dose of study treatment

Other illness

• Known bleeding disorders (example, von Willebrand's disease or hemophilia)
• Central nervous system (CNS) involvement or suspected Richter's syndrome

Other

• Presence of deletion of the short arm of chromosome 17 (del17p) or known TP53 mutation detected at a threshold of \>10 percent (%) variable allele frequency (VAF)

• Adult participants who are: (a) greater than or equal to (\>=) 65 years old or, (b) 18 to 64 years old and have at least 1 of the following:
  • Cumulative Illness Rating Scale (CIRS) score \> 6
  • Creatinine clearance (CrCl) estimated less than (\<) 70 milliliter per minute (mL/min) using Cockcroft-Gault equation
• Diagnosis of chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) that meets International Workshop on Chronic Lymphocytic Leukemia (iwCLL) criteria
• Measurable nodal disease (by computed tomography \[CT\]), defined as at least one lymph node \> 1.5 centimeter (cm) in longest diameter
• Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) Grade less than or equal to (\<=) 2
• Active CLL/SLL requiring treatment per the iwCLL criteria