As spotted by Nerd Leaks, trademarks for Pokemon Sun and Pokemon Moon have been spotted. There are two logos to accompany this too. Again, not confirmation, but I'd call this all convincing. Take a look:
Beyond that? We don't know too much. We certainly should hear a lot more about it tomorrow I'd imagine. I also think there is a fair chance that we could hear more news about other Pokemon ventures like Go aswell. I'll be on it, so stay tuned.