For a while, it was rumoured that pop megastar and friend of Ryan Reynolds Taylor Swift would be entering the MCU in a role in Deadpool & Wolverine. We've seen Swift act before in movies like Cats and Amsterdam, but she's not yet stepped into the spandex of a superhero role.
Earlier in the year, fans believed she'd be making a cameo as the superhero Dazzler in the movie. However, a report by EW points to that not being the case. There's still the chance that we could see Swift in her own superhero show, but not in Deadpool & Wolverine.
Even if Swifties flocking en masse could have pushed the Deadpool & Wolverine box office up by a significant margin, it's not like the film necessarily needs a pop star cameo. We could see plenty of returning stars as part of the film anyway, considering the TVA and multiverse is involved.