Obviously, both Star Wars and Star Trek have been massive cultural phenomenon, both widely regarded as being some of the best and most influential sci-fi. Because of their popularity, both series have seen a large amount of spin off material: Books, Comics, TV shows and Movies, video games, everything.
My question is: Is there any official content in which the two universes cross over?
As yet, there has not been a Star Wars/Star Trek crossover in film, TV, comics, toys or any other licensed property.
There have, however, been a considerable number of "easter eggs" that reference the two properties including the appearance of the Millennium Falcon in Star Trek: First Contact and R2-D2 appearing in Star Trek (2009)
Star Wars was sold to Disney, the sarlacc from Star Wars: Return of the Jedi was mentioned in Once Upon a Time in Wonderland "Forget Me Not". ...Wonderland is a spin off of Once Upon a Time. Once Upon a Time "The Stranger" had a quick shot of an Oceanic Airlines plane with the same logo as seen on Lost.
(We are now entering the J.J. Abrams TV universe.)
Lost crossed over with Alias twice. The first time was in Alias "Authorized Personnel Only" (part 2) when Driveshaft from Lost was mentioned; the second time was Alias "A Clean Conscience" when the flight from Lost was mentioned.
Alias introduced a drink called Slusho! A Slusho! beverage was seen on Star Trek (2009), which was directed by J.J. Abrams.
That is the most concrete series of links I can come up with for you. J.J. Abrams was involved heavily in Lost, Alias, and Star Trek (2009). Lost, Alias, and Once Upon a Time and its spin-off were on ABC around the same time. ABC is owned by Disney that also owns the Star Wars franchise with J.J. Abrams directing Star Wars: The Force Awakens and Star Wars: The Rise of Skywalker.
This path is very soft, so you can ignore it.
C3PO and R2-D2 appeared on a column in an Egyptian pyramid in Raiders of the Lost Ark. One of the shuttle craft in Star Trek: The Next Generation "Evolution" is named Indiana Jones. At the time, Indiana Jones and Star Trek were both owned by Paramount. George Lucas co-wrote the story for Raiders of the Lost Ark.
I know this is soft. Other than the previously mentioned appearances of R2-D2 in Star Trek (2009) (and Star Trek Into Darkness), this is the most direct route. However, be careful with this one. R2-D2 also appeared briefly in Transformers: Revenge of the Fallen, and there is an Imperial Shuttle in Firefly "Serenity". The last leads down a rabbit hole of space ships appearing in various places where they may not belong.
