A Real-world Study of Ibrutinib and Venetoclax (I+V) First-Line Treatment Given for Fixed-duration of Time in Participants With Chronic Lymphocytic Leukemia

Inclusion Criteria * Has a confirmed diagnosis of chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) requiring treatment according to international workshop on chronic lymphocytic leukemia (iwCLL) 2018 guidelines * Intented for the treatment with fixed-duration ibrutinib plus venetoclax treatment (I+V) according to the approved indication. Decision to start I+V treatment must have been taken before and independently of participant's inclusion in the study * Participant must sign an informed consent form (ICF) allowing source data verification in accordance with local requirements * Is able to read, understand, and complete the PRO instruments in local language and comply with completion of all patient-reported outcome (PRO) instruments Exclusion Criteria * Has a history of CLL/SLL treatment * Has received an investigational medicinal product (including investigational vaccines) or used an invasive investigational medical device within 30 days before the start of the study or the first data collection time point * Is currently enrolled or plans to participate in an interventional clinical study (participation in a non-Janssen sponsored non-interventional study or registry is allowed) * Falls under any restrictions or limitations preventing treatment with I+V as per the current approved label of ibrutinib or venetoclax in Romania