Testing the Addition of Anti-Cancer Drug Sonrotoclax, to the Standard Treatment Zanubrutinib, for Previously Untreated CLL/SLL

Inclusion Criteria: * STEP 0: This bone marrow or peripheral blood submission to Adaptive is mandatory prior to registration/randomization for real-time identification of the clone needed for MRD testing. The bone marrow sample should be from the first aspiration (i.e., first pull). Aspirate needle should be redirected if needed to get first pull bone marrow aspirate. It should be obtained as soon after pre-registration as possible to confirm registration eligibility * STEP 0: Patients must be diagnosed with CLL/SLL according to International Workshop on Chronic Lymphocytic Leukemia (IWCLL) 2018 criteria that includes all of the following: * ≥ 5 x10\^9 /L B lymphocytes (5000/μL) in the peripheral blood (CLL) or a lymph node biopsy demonstrating SLL with the below immunophenotype (SLL) * On morphologic review, the leukemic cells must be small mature lymphocytes * Immunophenotype of CLL cells (performed locally) must reveal a clonal B-cell population, which coexpress the B cell surface markers of CD19 and CD20, as well as the T-cell antigen CD5. Patients with bright surface immunoglobulin expression or lack of CD23 expression in \> 10% of cells must lack t(11;14) translocation by interphase cytogenetics * STEP 0: Patients must meet criteria for treatment as defined by IWCLL 2018 guidelines which includes at least one of the following criteria: * Evidence of marrow failure as manifested by the development or worsening of anemia or thrombocytopenia (not attributable to…