Inclusion Criteria:  Age ≥18 years at diagnosis  One of the following diagnoses that meet the international diagnostic criteria (iwCLL2018 and WHO2017)  Chronic lymphocytic leukemia (CLL) Small lymphocytic lymphoma (SLL) CLL-like monoclonal B-cell lymphocytosis (MBL) Retrospective cohort: CLL/SLL/MBL diagnosis between January 1st 2010 and August 31th 2021. Prospective cohort: CLL/SLL/MBL diagnosis between September 1st 2021 and September 1st, 2025. Signed written informed consent according to ICH/EU/GCP and national local laws (if applicable)  Exclusion Criteria:  - -