Inclusion Criteria:  Patients ≥18 years old at diagnosis Confirmed diagnosis of relapsed/refractory B-cell ALL or de novo AML diagnosed between 01 January 2015 and 31 December 2019 At least 1 line of treatment for R/R B-cell ALL or de novo AML within the study period  Exclusion Criteria:  Patients with no medical chart available Patients with unreliable data as per investigator's opinion (e.g. excessive missing data or inconsistence data) Patients that have participated in any interventional clinical trial for relapsed/refractory B-cell ALL or AML at any moment Patients with secondary AML Patients with any concomitant primary malignancy Patients with acute promyelocytic leukemia (APL)