Inclusion Criteria:  Existing or new diagnosis of acute or chronic GvHD treated with systemic steroid therapy (≥0,5 mg/kg/day) Sufficient German language skills Willing/ able to train at the provided exercise facilities or online twice a week Willing/ able to take part in the scheduled testing Capacity to consent Signed informed consent  Exclusion Criteria:  Any physical or mental conditions that would hamper the adherence to the training and/or nutritional program or the completion of the study procedures Heart insufficiency > NYHA III or uncertain arrhythmia Uncontrolled hypertension Severe renal dysfunction (GFR < 30%, Creatinine> 3mg/dl) Reduced standing or walking ability Insufficient hematological capacity (either hemoglobin value below 8 g/dl or thrombocytes below 30.000/µL) Any other comorbidities that preclude participation in the exercise programs