In a brief scene at the end of the Overwatch 2 Season 12: New Frontiers trailer, Blizzard teased a Warcraft crossover with the appearance of Frostmourne.
The scene at the end of the Season 12 trailer has a unseen shadow figure plunge Frostmourne into the floor of an icy cavern played over with the Lich King theme music. The upcoming support hero, Juno, then says, «Wait, what was that?»
What this Warcraft crossover looks like for Overwatch remains to be seen but could be a celebration event for World of Warcraft's 20th anniversary themed around the Lich King.
Several Blizzard titles have received Warcraft themed cosmetics lately including Diablo 4's new Warcraft cosmetic sets as well as a similarly themed Diablo Immortal x World of Warcraft Collaboration Event heavily featuring the Lich King. We've also datamined Frostmourne during the Diablo 4 Season 5 PTR suggesting we could be seeing more Lich King themed cross over events across several Blizzard titles soon.
We'll be sure to update you when we learn more, but for now the Season 12 Overwatch update is expected to release August 20th. Check out the trailer below which we've timestamped for the Warcraft teaser for quick reference: