At the Ubisoft Forward presentation earlier before, the company provided Mario + Rabbids Sparks of Hope another update about the game's final DLC. It reconfirmed it would be arriving later this year.
In addition to this, there was a short cinematic showing Rayman meeting the Mario Rabbids. You can see this brief scene play out at the 1:04:30 mark in the video above. The game's creative director even tweeted about it:
The second DLC 2 pack was also briefly featured in the same highlight reel - confirming this next DLC "was coming soon". In it, there was a look at the new character causing trouble for Mario and friends: