Testing Early Treatment for Patients With High-Risk Chronic Lymphocytic Leukemia (CLL) or Small Lymphocytic Leukemia (SLL), EVOLVE CLL/SLL Study

Inclusion Criteria: * Participants must have a confirmed diagnosis of chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) (collectively referred to as CLL throughout) according to the 2018 International Workshop on CLL. Participants must have been diagnosed within 18 months prior to registration * Participants must have CLL-International Prognostic Index (CLL-IPI) score \>= 4 and/or complex cytogenetics (defined as 3+ chromosomal abnormalities) * Cytogenetic AND/OR FISH analyses must be completed at a Clinical Laboratory Improvement Act (CLIA)-approved (or laboratories accredited under Accreditation Canada Diagnostics to conduct FISH analyses) laboratory within 18 months prior to registration. At minimum, FISH panel should use probes to detect for abnormalities in chromosomes 13q, 12, 11q, and 17p * TP53 gene mutation analysis performed at any CLIA-approved (or laboratories accredited under Accreditation Canada Diagnostics) lab (if completed) must be obtained within 18 months prior to registration. This sequencing test is distinct from FISH studies for del(17p) * Note: TP53 gene mutation analysis is recommended but not required if the participant meets disease-related study criteria via a combination of risk factors that totals a score of 4 on the CLL-IPI score and/or has complex cytogenetics completed * Immunoglobulin heavy chain locus variable (IgVH) gene mutation analysis performed at any CLIA-approved lab (or laboratories accredited under Accreditat…