Kind of like Nvidia GeForce Now - except that you get a full windows PC environment to play in, so theoretically you can play any game that runs on Windows.
I used it for a while, it’s pretty good, but the cost has risen a lot faster than the Hardware quality lately and now in order to have a “top spec” gaming pc it’s like $50/month.
Not a bad deal if you don’t game much, but want to check out a specific game for a month or two - or if you travel a lot but want the power of a full desktop. But if you just want a gaming PC, you’re probably better off building your own