Cryopreservation, or preserving biological tissue by cooling it to subzero temperatures, may bring to mind works of science fiction. Yet, researchers have been working on this technology for nearly 100 years. For most of the field's history, minimal progress was made—until 2023, when researchers from the University of Minnesota successfully transplanted a cryopreserved kidney to another rat, showing the potential for cryopreserved organ transplants in humans.