Define: “come out”
What counts as Unturned II “coming out?” Coming out in any playable state? The release of the next major demo build? Its release onto Steam in presumably Early Access? Full release?
If it’s the foremost, that happened a few months ago. If you’re counting U4’s combat demo, that’ll be this year (imo after Unity LTS update for U3, but could be before).
Full release would be impossible to give any sort of accurate prediction. Late-2019 EA release would be reasonable to predict, but not something that’d easily be set in stone to begin with. U3 gets priority when it really demands it, which can (briefly) slow development on U4 down. There’s also real-life stuff and all that.
But I’d say late-2019 is still reasonable enough to predict regardless. Full release I’d say would be 1–2 years after the initial EA release (if there is one).