There have been dreams of bringing back extinct animals like mammoths, but, as Discover magazine writes, even if mammoths could be resurrected, they wouldn't necessarily act like mammoths of old.
In 2017, Newsweek reported that two labs were trying to resurrect the woolly mammoth — Sooam Biotech in South Korea and George Church's lab at Harvard Medical School. Church had previously announced in 2015 that his lab had been able to insert 14 mammoth genes linked to cold resistance into elephant cells using CRISPR and said in 2017 that they'd made 45 edits to the elephant genome to make it mammoth-y and that the next step would be to develop an elephant with mammoth-like traits.
But as Discover magazine writes, efforts like these might never yield a true mammoth. It notes that genetic findings have increasingly suggested that what were once thought to be separate species of mammoth might be one interbreeding population with a range of traits. Additionally, it says that even if a genetic version of a mammoth could be resurrected, it might not behave like a mammoth in the absence of mammoth elders to teach it mammoth behaviors.