A Study to Assess Change in Patient Experience in Adult Participants With Chronic Lymphocytic Leukemia (CLL) Receiving Oral Venetoclax Tablets + Intravenous Rituximab or Bruton's Tyrosine Kinase Inhibitors Tablets in the United Kingdom

Inclusion Criteria: * Has a confirmed diagnosis of chronic lymphocytic leukemia (CLL) (as defined by 2008 Modified International Workshop for Chronic Lymphocytic Leukemia National Cancer Institute Working Group (IWCLL NCI-WG) Guidelines). * Has relapsed/refractory (R/R) disease having received only 1 prior line of treatment, which must have been a chemotherapy or chemoimmunotherapy treatment. * Has treatment experience with venetoclax+rituximab (Ven+R) or bruton's tyrosine kinase inhibitor (BTKi)s that meets the criteria for inclusion described in the protocol, for which recruitment targets have not yet been met. Exclusion Criteria: * Previously treated with a BTKi, a BCL-2 inhibitor or other investigational agents. * Has any other medical condition or disorder that, in the opinion of the site investigator or study director, could compromise participant's ability to give written informed consent and/or prevent or interfere with his or her ability to comply with study procedures and provide meaningful information about his or her CLL experience.