Renegade Roundup is a new battle mode in Mario Kart 8 Deluxe.
The mode is part of the Battle Mode. In this mode, the players are split into two teams. One team uses piranha plants to attack and capture the other team, the renegades. When a renegade is attacked by an enemy's piranha plant, they will be sent to a cage on the map. Free renegades can allow their captured allies back into the game by flipping the key switches under the cages.
The capturing team wins by capturing all the renegades before the time runs out, while the renegades win by avoiding being captured by the enemy team until the time runs out.
This battle mode's rules are very similar to Cops n' Robbers.