The games are named: ~Let's Go, Pikachu!~ and ~Let's Go, Eevee!~ and are, as said earlier, based on one of the first Pokemon games which took place in the Kanto-region.
This game also comes with a new Switch controller which looks like a pokeball and is, possibly, used for catching pokemons.
Nintendo also announced the newest 'classic' pokemon games which will be released late 2019.
Also released is a free Pokemon game for the Nintendo Switch called 'Pokemon Quest'. It is downloadable since today and takes place on 'Tumblecube Island'.