Aims : to highlight the different complications of immunosuppressed patients; to focus on difficult-to-manage respiratory infections and innovative approaches such as phage therapy and its application, and preventive and treatment strategies for fungal pulmonary infections; to address the pathogenesis and treatment approaches of noninfectious complications, either immune-driven (chronic lung allograft dysfunction (CLAD) and graft-versus-host disease (GVHD)) or drug-related.