Pokemon Black 2 and Pokemon White 2 has been announced, and is the first Pokemon game with a number on it. What's even weird about this new title is that it's for the Nintendo DS, not the 3DS. It was announced during a tv show in Japan called Pokemon Smash and revealed the sequel will hit Japan on June.
For the people that have a 3DS, you can still play the game but only in 2D. Have no idea why they didn't bother making it a 3DS title, maybe more Pokemon players have a DS? your guess is good as mine.
In terms of what is included in the sequel is still unknown. The reveal happened a few days ago so expect more news to hit the web in the next few weeks.
A US version of Pokemon White and Black 2 is confirmed to be released during this year. No exact date yet.