Lightning McQueen races in the fictional Piston Cup championship series throughout Pixar's Cars.
The Piston Cup is the major stock-car racing competition in the Cars universe. McQueen enters the first film as a rookie competing for the championship and becomes one of the series' most prominent racers.
Its presentation draws on American stock-car racing, including oval tracks, pit crews, sponsors, and championship points. Dinoco is a major sponsor within the series, while Rust-eze sponsors McQueen during much of his early career.
The World Grand Prix is a different competition introduced in Cars 2, where racers compete internationally. It is not the name of McQueen's main domestic championship. Similarly, the Florida 500 is a specific race in Cars 3, not the title of the full series.