Nintendo released two expansive and impressive DLC packs for Mario Kart 8 in 2014 and 2015, containing new tracks and characters to race as with some other Nintendo IP joining in on the fun; Link as a playable racer and getting a Hyrule Field Race track and F-Zero getting two courses across the DLC packs. And we might be getting more if this Nintendo of Europe Tweet means anything.
If we do get more Mario Kart 8 content, it would be a smart move to inject more content support for the Wii U this year, as it is not getting much during the summer months outside of #FE. More on this as the story develops.
Source: Nintendo of Europe Tweet