Nintendo has announced three different retail versions of Splatoon 2 for Japan. The download version comes with a game case, but no game card.
According to Nintendo, there is a standard Splatoon 2 package version, which comes with the game case and the game card. Then, there is the Splatoon 2 download version, which will look something like this and contain a download code:
[Source: kotaku.co.uk ]