Outlast and Outlast 2 Switch ports are incoming. Right now, we know for sure that both ports will hit the hybrid system in Q1 2018.
Developer Red Barrels announced the ports via Facebook, thanking fans for sticking around for the last five years, detailing a little more about the future of Outlast, and what fans can expect next year. We don't have a specific release date/price point yet, and no details have been released whether if either port will have any exclusive or additional content.
As for the future of the series, the post details DLC is not in the works for Outlast 2. Fan's cries have been heard regarding more content, but according to the developer the title simply wasn't made with DLC in mind, unlike its predecessor.
Part of the issue with DLC for Outlast 2 is that the ideas just don't work as additional content. The game was designed to "make you feel like a rat in a maze, without any knowledge of what’s outside the maze." Not all hope is lost, however. The team is working on a new Outlast-esque experience, though it won't be a sequel.
"Currently we’re working on something a lot of you have been asking for... It won’t be a sequel to Outlast or Outlast 2, but it will be a distinct experience set in the Outlast universe. We can’t say more right now, we first need to make sure we can make it work. Like I mentioned, we strive to be risk-takers and this one is a pretty big challenge. If all goes well, we’ll soon be able to reveal more."