In this episode of ASTCT Talks, Dr. Shernan Holtan welcomes Andrew Lin, Manager of Clinical Pharmacy Services of Adult BMT and CTS at Memorial Sloan Kettering Cancer Center, to discuss the evolving role of tacrolimus levels in GVHD prophylaxis within the post-transplant cyclophosphamide (PTCy) era. They explore findings from a recent retrospective study examining whether higher tacrolimus levels offer added protection against GVHD, what this means for toxicity and patient outcomes and how these insights are shaping dosing strategies. The conversation also looks ahead to future research areas, including MMF optimization and the potential for simplified, patient-centered prophylaxis regimens.