Pioneering work in xenotransplantation achieved a milestone with a genetically modified pig lung transplant into a brain-dead human patient, maintaining organ functionality for nine days. This first-of-its-kind procedure involving an organ directly exposed to external pathogens demonstrated absence of hyperacute rejection due to alpha-gal knockout modifications but revealed signs of ischemia reperfusion injury and antibody-mediated rejection developing over the observation period. The advancement contributes critical knowledge toward overcoming immunological barriers in xenotransplantation.