3.1. Overview Prospective, multicenter, observational cohort study comparing short-term PROs measured with the HM-PRO between two exposure groups: patients undergoing allogeneic stem cell transplantation (allo-SCT) and patients receiving CAR-T cell therapy. Patients will be enrolled at hospital admission for the index inpatient procedure and followed through the inpatient stay (admission → discharge). The study is non-randomized and designed to describe trajectories of symptoms and HRQoL and to estimate the between-group difference in deterioration of HM-PRO scores (primary estimand: mean difference in change score, CAR-T vs allo-SCT).