Sonic will be appearing in the upcoming Samba de Amigo: Party Central, along with a couple songs and a location from the franchise.
Party Central’s base game will feature the songs Fist Bump and Escape From the City. It will also feature City Escape as a location, where Samba can dance alongside Sonic himself.
Check out a screenshot from the Sonic stage below:

This isn’t the first time the two franchises have crossed over: being a Sonic Team-made IP, Sonic’s got a long history with the series. Sonic music appeared in the original game and it’s expanded Japanese-only expansion, and the Wii version did one better by actually bringing in Sonic and featuring Green Hill as a location.
Given that Party Central will feature DLC, it seems likely that the game will get more Sonic content in the future.