Pizza planet did you remember? the first Toy Story?
Toy story was the first CGI-made animated movie in the industry and it was a massive success with Pixar & Disney, following this success Disney signed with Pixar to produce more movies
Do you remember that truck where Buzz Lightyear and Woody were stuck ?
Yes that one, (if you didn't watch Toy Story shame on you, you should ^^') well to memorize that truck that was in the first studios movie and the one that led to it's success since 1995, the Pixar team decided to put it in almost every movie (and even sometimes as a character)
Here is every time a Pizza planet truck showed in a Pixar Movie :
Waiting for incoming Pixar's Onward + Soul to update the article ^^