Splatoon 2 DLC Coming This Summer

Another highlight announcement from Nintendo’s latest Direct is that there will be an single player expansion for Splatoon 2 coming later this year.
For the first time you will be able to play as an Octoling in the Splaton 2 Octo Expansion. The DLC will feature a new underground facility to traverse in as the player make their way back towards Inkopolis.
The story of the game will have up to 80 single player missions and will feature more for those when finishing the game, unlocking Octolings (Girl or Boy) as a playable character for multiplayer. And those who pre-purchase the game now will instantly receive octo-themed gear for multiplayer.
Source: Splatoon