The study looks at how well the drug venetoclax works when added to another treatment called a covalent Bruton's Tyrosine Kinase Inhibitor (cBTKi) for people with *Chronic Lymphocytic Leukemia* (CLL). CLL is a type of cancer that affects blood and bone marrow. The goal is to see if this combination can make the cancer disappear so much that it can’t be measured in the blood anymore. This is called *undetectable measurable residual disease* (uMRD). If successful, patients might have an *off-treatment period*, meaning they could stop taking the medication for a while. To join the study, patients must have been on a stable dose of cBTKi for at least six months and show improvement. They must also be healthy enough based on specific criteria. However, people with certain medical conditions or who have used similar medications before may not qualify.

• Study requires a stable cBTKi dose for 6 months before joining.
• Participants must have specific health criteria met.
• Some past medical conditions may prevent joining the study.