The rookie race car trained by Lightning McQueen in Pixar's Cars 3 is Cruz Ramirez.
Cruz is introduced as a trainer at the Rust-eze Racing Center, where she uses modern simulation technology to help Lightning prepare for competition. Lightning initially believes he needs conventional coaching, and the two clash over his changing performance.
As the story develops, Cruz reveals that she has always wanted to race but was discouraged by expectations about what kind of car belongs on a professional track. Lightning recognizes her ability and helps her enter the racing world.
Cruz ultimately becomes a major competitor rather than remaining only a trainer. The character is voiced by Cristela Alonzo. Cars 3 was released in 2017 and centers on Lightning's response to a new generation of faster race cars.