The Region of Alola is based on the Hawaiian Islands, making this and it's companion game, Sun Version the second entry in the Pokémon franchise to be based on a region in the United States.
Sun and Moon are the first Pokémon games to be released in Chinese.
Unlike its predecessors (Pokémon X and Y, Pokémon Alpha Sapphire and Omega Ruby), where the stereoscopic 3D feature of the Nintendo 3DS was used sparingly (like during battles), this game and its counterpart Pokemon Sun don't use this feature at all.
Along with Sun, this is the last game to included EVERY pokemon. By the next game, there were just too many to program.
This is the first game to introduce regional forms. Past pokemon with different types that adapted to foreign environments.