In Pixar's Cars 3, Doc Hudson appears in flashbacks as Lightning McQueen's mentor.
The flashbacks show Doc training with a young McQueen before the events of the first Cars. They reveal the depth of their relationship and explain why McQueen struggles emotionally after Doc's death and after his own crash against Jackson Storm.
Doc's former crew chief, Smokey, helps McQueen understand that Doc's career did not end with failure. Instead, Doc found meaning through friendship and mentorship. The film uses these memories to connect McQueen's new role with Doc's legacy. Doc Hudson was voiced by Paul Newman in the first film, while archival material contributes to his presence in Cars 3.