The next Pokemon games will be called: Pokémon Pre and Pokémon After.
The games were in development for 4 years, the original plan was to put the franchise on a stop and make an advanced WiiU game to help the console sales,
Nintendo anyhow wanted to boost the 3DS sales and make a Pokemon game on the Switch at the same time, Pokémon Pre and After got delayed and Game Freak used the 7th Generation as a test.
Ohmori suggested to add the Ultrabeasts and Z-Moves to see the players reaction before changing the gameplay. Knowing that most of the players like more the traditional games,
Ohmori decided to make 2 total different version for the Switch

Pokemon Pre will take place in a Kanto totally different from the one we know today, it will have more water, a big desert and a colossal forest,
there will be only Pokémons from Generation 1, 2, 3, 4 and 100 Pokemons from Generation 8 to symbolize the series past.
No major changes in the gameplay.
Legendary MxA

Pokemon After will take place on an island bigger than Alola and Hoenn fused together, there will be a major focus on the story unlike Pokemon Pre,
there will be only Pokémons from Generation 5, 6, 7 and 100 Pokemons from Generation 8 to symbolize the series present and future.
Strong changes in the gameplay, sophisticated battle system taking base from Fighting games and mixing it with the well know Pokemon formula.
Legendary DL: Kagsam/Hiksam