E3 2017 was a big welcome for fans of Pokemon as it was the place where it was confirmed by Nintendo that we will see a mainline Pokemon game come to the Nintendo Switch. Eventually.
It is almost at the right time for the speculation on what form this game would take (as if we weren't doing it regardless of an official confirmation). It could be some kind of extended cut port of Pokémon Sun and Moon, it could be an entirely new sequel, at the very least we know it's going to be a core addition and not just another side title like Pokken Tournament.
Although, there isn't a specific date for the release of Pokemon on Ninetendo Switch but the Nintendo's Q1 2018 financial reports have given a hint at the very least which gives us a tip of when the game will be released.
In the company's list of upcoming games it has Pokemon RPG for Nintendo Switch listed as due for release in '2018 or later'.