Cars 2 was the first Pixar Cars film released in Disney Digital 3-D.
Released in 2011, Cars 2 was presented in Disney Digital 3-D as well as conventional formats. The sequel’s globe-spanning action, nighttime races, aerial sequences, and spy set pieces made stereoscopic presentation a prominent part of its theatrical marketing and exhibition.
The original Cars premiered in 2006 as a conventional 2-D animated feature. Cars 3 followed in 2017 and also received 3-D presentations, but it was not the first franchise entry to do so. Thus the answer is the middle film rather than the original or the later sequel.
Cars 2 expands the setting far beyond Radiator Springs. Its main locations include Tokyo, Porto Corsa, and London, and its plot combines the World Grand Prix with an espionage story involving Finn McMissile and Holley Shiftwell. The film was directed by John Lasseter and Brad Lewis and released by Walt Disney Pictures.