Compared with traditional storage media, biological data storage has advanced more rapidly in capacity, diversity, and lifespan, and it also enables continuous data retention. The DNA molecule, as Nature's own archival medium, provides unparalleled density, longevity, and passive durability, making it a compelling foundation for the next generation of "cold" and "deeply cold" archives. Since 2019, progress across the stack—coding for insertion–deletion–missing channels, large-scale random access, enzyme writing, nanopore-native retrieval, and chemically robust expansion—has transformed DNA storage from provocative demonstrations into mature technologies with early end-to-end prototyp... More >