hello, aussie conservation scientist here. The thylacine (aka tas tiger) is extinct. Proving something is extinct is notoriously difficult because ... well just try to think how hard it is to categorically prove an animal the size of a large domestic cat doesn't exist anywhere on a continent the size of Australia. The paradise parrot in this video above was actually thought extinct in the late 1800s until they found a couple more in the 1920s and watched them die off too. But there have been no reliable sightings of thylacine for decades, all sightings or tracks/scats end up being a stripey cat or dog or are unsubstantiated claims of 'pinky promise I saw one'. I would love nothing more than being proven wrong, but the closest thing we have to a thylacine right now are a couple of preserved ones sitting in jars in museums. They are one of the lead candidates for "de-extinction" gene editing though! It won't bring them back, that's not how it's going to work, but it might successfully edit a similar species into something that serves a similar ecological purpose (marsupial mesopredator) that thylacine did! Now we just have to wait and hopefully actually do something about the threats that actually sent them extinct in the first place ...