According to a report from Kotaku’s Jason Schreier, which is largely about the failings of the studio behind Mafia III, an unnamed 2K Games studio is working on the next game in the Bioshock franchise. Below is a tweet that drew people’s attention and started this whole festival of rumors:
The game itself is in development and codenamed “Parkside”, but it’s still very early in it’s lifecycle. I wouldn’t expect any confirmations for at least the rest of 2018. Sources have said the Parkside isn’t ready for public demos or consumption yet. So that rules out this new Bioshock title being the game 2K fans are expecting see released in 2019. We’ll just have to wait and see what the future holds for this new game and 2K as a whole.