A field review assessed progress and outstanding challenges for mitochondrial gene therapy, detailing advances in delivery vectors, allotopic expression and mtDNA editing techniques. Researchers noted promising preclinical efficacy in models of mtDNA disorders but emphasized barriers: heteroplasmy management, efficient mitochondrial targeting, immunogenicity and scalable manufacturing. The review calls for standardized efficacy metrics, regulatory guidance specific to mitochondrial modalities and investment in vector platforms to move candidates toward human trials.