Who becomes the new racer for the Rust-eze team at the end of Cars 3?

Cruz Ramirez becomes the new racer for the Rust-eze team at the end of Cars 3.

Cruz begins the film as Lightning McQueen's trainer at the Rust-eze Racing Center. She has technical knowledge and strong driving ability, but she has been assigned to coaching rather than competing because of assumptions about her place in racing.

During the Florida 500, Lightning realizes that Cruz can challenge Jackson Storm. He gives her his racing number and lets her take over the race, where she wins. The ending then shows Cruz becoming Rust-eze's new race car while Lightning adopts a mentor role.

Cruz's victory is distinct from Lightning's earlier Piston Cup wins. It also completes the film's broader theme: racing careers can change, and passing knowledge to a new competitor does not mean abandoning the sport.