A Study to Investigate Progression-Free Survival With Sonrotoclax Plus Obinutuzumab Or Sonrotoclax Plus Rituximab Compared With Venetoclax Plus Rituximab Treatment In Patients With Relapsed and/or Refractory Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CELESTIAL-RRCLL)

Inclusion Criteria:

• Confirmed diagnosis of CLL/SLL that meets the International Workshop on ChronicLymphocytic Leukemia (iwCLL) criteria

• Received one or more prior therapies for CLL/SLL. For each line of therapy,participants must have received at least 2 cycles of the therapy

• Participants with prior BCL2i exposure are eligible if remission duration was ≥3years with ≥2 years from last BCL2i intake

• Eastern Cooperative Oncology Group (ECOG) Performance Status score of 0, 1, or 2

• Adequate organ function

Exclusion Criteria:

• Known active prolymphocytic leukemia or currently suspected Richter's transformation

• Prior autologous stem cell transplantation or chimeric antigen receptor T-celltherapy within 3 months before first dose of study drug

• Prior allogeneic stem cell transplant with active graft-versus-host disease (GVHD),requiring immunosuppressive drugs for treatment of GVHD, or have taken calcineurininhibitors within 4 weeks prior to consent

• Known central nervous system involvement by CLL/SLL

• Severe or debilitating pulmonary disease

• Clinically significant cardiovascular disease

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