Inclusion Criteria:  ≥18 years old Physician-confirmed diagnosis of CLL or small lymphocytic lymphoma (SLL) BTKi naïve patients who initiate acalabrutinib or ibrutinib treatment alone or in combination with an anti-CD20 mAb within 7 days (before or after) study enrollment*. Both treatment naïve and relapsed/refractory CLL patients will be included. Provides informed consent Adequate English reading skills Able to access and use a computer, tablet, or smartphone to complete PROs  Exclusion Criteria:  Use of BTKi any time prior to study enrollment. Currently receiving systemic treatment for another malignancy Currently enrolled in a clinical trial