You might not believe it, but according to the dev team working on Redout, it's still coming to Switch. This was a title announced before the Switch even came out, but the game still hasn't seen release. In a recent Fragments of Silicon interview, Guiseppe Franchi of 34BigThings reconfirmed that the title is still coming.
“Yes, very much (still in development). … It’s been long overdue and we know it. As I said before, it was challenging to bring this game on Xbox and PlayStation, so I’ll let you know how imagine how challenging it was to bring it on Nintendo Switch. But it’s still coming. We are in the process, we are in a very advanced… We’re very close to it. It’s coming.
The game is going to be published by Nicalis, so as for the release, I suggest you ask them. Not because I don’t want to talk or because I don’t know, but because it’s their job. … they’re doing their job perfectly well. From our end though, we’re wrapping things up.”