In Pixar's Cars 3, Cruz Ramirez is the trainer who helps Lightning McQueen prepare for his comeback.
Cruz works at the Rust-eze Racing Center and uses modern training methods, simulators, and data to help racers. Lightning initially doubts her approach because he wants to train in the traditional style associated with Doc Hudson.
Their relationship changes during a road trip and a series of training challenges. Cruz is not merely a coach: she is also a talented racer whose own ambition has been limited by expectations about what role she should play.
The film ultimately shifts the story from a simple comeback attempt to a partnership. Cruz's development is why the question is sometimes confused with one about Lightning's chief rival, Jackson Storm, who is a racer rather than a trainer.