Observational Study of CLL/SLL Treatment and Ibrutinib Treatment of CLL/SLL in Routine Clinical Practice

Inclusion Criteria: * In the retrospective part: 1. Male or female patients above 18 years old 2. Patients underwent CLL treatment after Jan 1st, 2013 3. Patient understand and voluntarily sign an ICF, if applicable. * In the prospective part: 1. Male or female patients above 18 years old 2. Patients diagnosed with CLL，including treatment- naïve patients or patients who have received ≤3 prior therapies 3. Patients treated with ibrutinib as monotherapy or a part of combination therapy 4. Patient understand and voluntarily sign an ICF. Exclusion Criteria: * In the retrospective part: 1. Patients with documented diagnosis of other cancers prior to the diagnosis of CLL 2. Patients enrolled in interventional clinical trials of any drug for CLL treatment * In the prospective part: 1. Patients with documented diagnosis of other cancers prior to the diagnosis of CLL 2. Patients with contraindication listed in the package insert of ibrutinib 3. Patients enrolled in interventional clinical trials of ibrutinib or any other drug for CLL treatment 4. Patient received Ibrutinib treatment as maintenance therapy.