Reportedly, the latest X-Men movie, Dark Phoenix, doesn't have a post-credits scene. Dark Phoenix is the final mainline X-Men movie as part of 20th Century Fox's X-franchise. The series kicked off way back in 2000's X-Men, which inspired a full trilogy that concluded with X-Men: The Last Stand, an adaptation of The Dark Phoenix Saga comic book storyline. However, The Last Stand wasn't well received by comic or movie fans, and Fox ultimately rebooted the franchise with X-Men: First Class.
Then, Fox merged the timelines in X-Men: Days of Future Past, and introduced younger versions of classic X-Men characters with X-Men: Apocalypse. Now, Dark Phoenix further follows the characters from the prequel series and the new versions of previously established heroes, like Scott Summers aka. Cyclops (Tye Sheridan), Storm (Alexandra Shipp) and Jean Grey (Sophie Turner). However, with Disney acquiring Fox's film and TV assets in the recent blockbuster deal, Dark Phoenix is expected to be the last main X-Men movie before Marvel Studios reboots the franchise - with the exception of Deadpool.
As such, it should come as little surprise that EW reports Dark Phoenix doesn't include a post-credits scene. Though it could feasibly have a stinger setting up New Mutants - the actual last Fox X-Men movie set to be released - Dark Phoenix reportedly won't use include any tags at the end.
Though Marvel Studios is perhaps best known for their use of post-credits scenes in the Marvel Cinematic Universe to set up future movies, other franchises, particularly those based on comic book superheroes, have used button scenes as well. X-Men in particular has used them in the past, but they're generally contained to their respective series. For instance, a Days of Future Past post-credits scene set up Apocalypse, and Deadpool teased its own sequel. In that regard, it makes sense Dark Phoenix wouldn't have one, since New Mutants is a separate movie in the larger universe, and there aren't expected to be anymore X-Men movies in this continuity.
With that said, movies can use post-credits scenes or audio cues to add something fun at the end of a film without setting up a future installment. Considering Dark Phoenix will be the final installment in an X-Men franchise that has spanned nearly two decades, it would be a nice touch to include something that honors its legacy, especially since Disney and Marvel Studios will no doubt launch an entire new franchise as part of the MCU. How Dark Phoenix could do this is up to director Simon Kinberg, himself a long-time producer in the X-Men franchise.
But no matter whether Dark Phoenix does include anything at the end of the credits, fans will no doubt be curious to check out the final X-Men movie in this series. It remains to be seen if Dark Phoenix satisfyingly adapts The Dark Phoenix Saga from the comics, and offers casual fans a compelling conclusion to the franchise. Fans will get to see for themselves when Dark Phoenix hits theaters in June.