Long before Shazam! cast Zachary Levi to breathe life into DC Comics' World's Mightiest Mortal, Dwayne "The Rock" Johnson was hired to play Black Adam in the DC Extended Universe. Originally the plan was for Black Adam and Shazam to clash in the latter's first movie, but that's been delayed in favor of the powered Billy Batson going up against Doctor Sivana first. But in addition to Black Adam and Shazam eventually coming to blows on the big screen, there have also been rumblings that Johnson's Black Adam and Henry Cavill's Superman could fight each other. While nothing has been officially confirmed yet, Cavill recently noted that there has been movement behind the scenes towards making that happen. As Cavill explained:
There's definitely some kind of work towards that. There's a lot of things spinning around in the universe right now with that. Obviously if Black Adam does become a character officially, [Dwayne Johnson] will play him. I'm pretty sure it'll be a Shazam/Black Adam thing first. If it does happen, it would make sense that way, but you never know. Maybe it'll be a Superman movie and Shazam will come and help. That's kind of stealing his limelight though, which is not cool.
Dwayne Johnson has expressed interest in his version of Black Adam handing a beatdown to Superman, and while it's still unclear when this might happen, Henry Cavill's comments to MTV imply that is something the folks affiliated with the DCEU are interested in, too. With Superman back among the living following the events of Justice League, the Man of Steel is back to protecting the innocent, so you can bet that if Black Adam starts causing a ruckus (particularly if it's close to Metropolis), Superman would intervene. That said, Cavill does make a good point that we're likelier to see Shazam go mano a mano with Black Adam first, but it would still be cool to see the Big Red Cheese and the Man of Steel join forces to take down the Kahndaqian anti-hero, just like they did in the animated short movie Superman/Shazam!: The Return of Black Adam.
Right now the DCEU's time table for bringing in Black Adam is shrouded in mystery. In January 2017, it was announced that Black Adam would receive his own standalone movie, and if I had to guess, I'd say that this story would be set thousands of years ago and show how the man once known as Teth-Adam received his powers from the Wizard Shazam. Then last November, it was rumored that Suicide Squad 2 would follow Task Force X traveling to Kahndaq to deal with Black Adam, who has been labeled a weapon of mass destruction. Neither the Black Adam movie nor Suicide Squad 2 have been dated yet, and with Dwayne Johnson busy with plenty of other projects, we may be in for an even longer wait to see his character cause trouble for Shazam, Superman or both.
As for Superman, Man of Steel 2 is still being discussed, but it remains to be seen if that will be one of the many DCEU projects to get the green light. We are at CinemaBlend will bring you more updates on Black Adam, Superman and the rest of the DCEU as they come in. For now, you can look forward to watching Billy Batson become a superhero when Shazam! is released on April 5, 2019.