In Pixar's Cars 3, Cruz Ramirez directs Lightning McQueen's training at the Rust-eze Racing Center.
Cruz is a high-performance trainer assigned to help Lightning compete against Jackson Storm, a new generation of faster racers. She uses simulators, exercise routines, and data-driven methods associated with modern racing technology. Lightning initially resists her approach because he wants to prepare according to older racing traditions.
The relationship changes as Lightning and Cruz work together. Their training journey takes them away from the controlled center and into practical lessons connected to dirt-track racing and Doc Hudson's experience. Cruz gradually becomes more than a trainer: her own ability and racing ambitions become central to the film's conclusion.
This question concerns Cruz's role in Cars 3, not the racing alias she later uses. The film presents her as Lightning's trainer before revealing her potential as a competitor.