Kojima’s next thing is Death Stranding: https://en.wikipedia.org/wiki/Death_Stranding
Even after seeing both trailers, I also don't even know what Kojima's next thing is
Kojima is a lot like Steve Jobs, in a way. He has a vision of what things could be, that often transcends the current genre categories. Or in other words he knows what we want even before we know what we want.
(hopefully less dying of treatable cancer because of fruitatarian beliefs though)
Although unlike Jobs he definitely does also have a track record of getting stuck in development hell too.