Zack Snyder, the director of Batman v Superman: Dawn of Justice, told fans on Vero that the "real" Doomsday is still out there somewhere in the DC Universe.
In the film, Lex Luthor created Doomsday by subjecting the corpse of General Zod to a genetic procedure on board the Kryptonian scout ship crashlanded in Metropolis. Dialogue hinted, though, that there had been a previous version of the monster created on Krypton, and that Luthor's abomination would be the first since such experimentation had been forbidden.
When a fan asked about this, Snyder confirmed, "Yes, the real Doomsday is out there still."
In the comics, Doomsday was created millennia ago on Krypton, when a scientist named Bertron set about trying to create a living weapon through accelerated evolution, abusing and murdering a creature over and over again, then using its biological material to create a clone and do it all over again.
The eventual result was Doomsday, who managed to finally kill not only the creatures in Krypton's outlands, which had been responsible for the deaths of previous versions of Doomsday, but also his creator and Bertron's staff.
In the special features on the Man of Steel Blu-ray, Bertron was name-checked along with Doomsday. The decision to involve Lex Luthor with Doomsday's rampage is not entirely new -- he discovered the dormant creature and provoked it to life in the animated movie Superman: Doomsday -- but a more comics-accurate version of Doomsday came to Krypton this season, and will continue on as a threat in season 2.
Between the Bertron Easter egg and the Kryptonian archives referencing past events in Batman v Superman, it seems likely that by "out there," Snyder means Doomsday is still alive, likely in space, and not that he is "out there" in the sense that there were imminent plans to use him.
Snyder and Henry Cavill (who plays Superman) had both expressed admiration for "The Death of Superman," the 1992 story in which Doomsday first appeared. Elements of the story, including the death itself, were incorporated into Batman v Superman.33comments
When Doomsday first appeared in the comics, he was an anonymous, unexplained force of nature, with his tied to Krypton coming out only later in a subsequent miniseries by Doomsday creator Dan Jurgens.
Justice League is now on home video. The DC Extended Universe continues with Aquaman on December 21st, Shazam! on April 5, 2019, Wonder Woman 2 on November 1, 2019, Cyborg in 2020, and Green Lantern Corps in 2020.