It appears to one of those awful unlicenced apps that just provides a platform for people to run their own clubs on. Like PPPoker and Pokerbros. If it is then you are entirely at the trust of whoever you give your money to. I wouldn't go near these apps.
I have played a little on Pokio. Deposited, won a little over about two months, and cashed out with no problem.
You basically need to join one of the clubs hostning games on the platform. The clubs do not use the agent system that some other apps use, but you deposit via card or bank transfer (card options are limited though). It is not unregulated: Pokio is regulated via the Malta Gaming Authority, like some major online rooms, and seems legit from my experience.
As for the gameplay, it is kind of wild with a lot of very loose gambler types. The software is pretty good.
The main negative for me was the limited deposit options - but it might be better in other places (I live in a heavily regulated market).