Based on the time CD Projekt Red needed to complete The Witcher 3, it was estimated that the game would probably only arrive in 2018 since this new Cyberpunk 2077 is going to be a lot bigger than The Witcher 3.
It is hard to imagine a game that is even bigger than the Witcher 3. We were already blown away by how big the map is and we can’t wait to see what CDPR has in store for us in this upcoming game.
Although the game is bigger, they should take less time to complete the game. The developer did say that working on The Witcher 3 taught them a lot about how to create huge game. They also said in an interview recently that they have more people working on Cyberpunk 2077 now than they had when the Witcher 3 development was at its peak.
There is not a whole lot of information about Cyberpunk 2077 now so all we can do is wait until more details arrive.