The premise is to pick an animal species which has been hunted or otherwise pushed into exinction by humans in our timeline and somehow have it survive well into the 21st century, probably by sheer luck. How well would they do now? Would their population stabilize, would they firmly remain on the list of threatened species, would they still be among the first to go extinct eventually? I would think a lot of arctic species could still be around today if passing ships hadn't relied on them for provisions quite so aggressively. If steller's sea cow or the great auk survived that era of sea travel, even if just hanging on by a thread, then I could easily see them become "normal" arctic species to us like walruses or polar bears. Stil severely threatened, perhaps, especially by climate change, but far from fading into distant memory as they are in our timeline. On a sidenote, do you think that extinction at the hand of humans is a "meritocracy", meaning that if a species dies out, this necessarily means it has been more fragile than other species in the first place? So for instance, in no timeline coild the walrus go extinct before steller's sea cow, unless something truely bizarre happens.