New Pokémon are coming to Pokémon Go globally as part of the upcoming Pokémon Go summer tour 2018.
The Alolan forms of Diglett and Geodude will appear globally for the first time in Pokémon Go beginning 14th and 15th July (the weekend Pokémon Go Fest 2018 takes place in Chicago).
Meanwhile, Trapinch, Feebas and other Pokemon featured in the habitats of Pokémon Go Fest will appear more frequently all over the world during that weekend. The Cheering Pokémon, Plusle and Minun, will also appear more frequently worldwide (catching Plusle and Minun gets you bonus Stardust and a chance at finding their shiny versions).
Earlier, on 30th June and 1st July (the weekend the Safari Zone event takes place in Dortmund, Germany), all Pokémon Go players will see increased appearances of the grass and poison-type Pokemon originally discovered in the Hoenn region, Roselia.
There's more on the Pokémon Go summer tour 2018 on the Pokémon Go website.