Inclusion Criteria:  Written informed consent Single or bilateral lung transplantation On twice daily tacrolimus with stable trough levels in target range Participant in the TransplantLines biobank study in the UMCG  Additional criteria for Conversion cohort:  At least one year after lung transplantation with a stable clinical course and lung function eGFR >30ml/min*1.73m2 calculated with the CKD-EPI formula  Exclusion Criteria:  Administration of mTOR inhibitors; everolimus, sirolimus Quadruple immunosuppression Renal transplantation The subject has any disease or condition that might interfere with completion of this study or reaching the primary endpoint (e.g., life expectancy of <3 years, renal replacement therapy at start study)