Gamescom is the biggest videogame trade show in the world: It drew 370,000 visitors in 2018, compared to just over 69,000 for E3. It's open to the public while E3 is, technically at least, mainly an industry-only event, which is obviously a big factor in that difference, but even so there's no denying that it's major international event. Despite that, Blizzard has decided to skip it this year.
"As part of a renewed effort this year to maintain our focus on development, for our current games and our future projects, we won’t have a booth at Gamescom 2019," Blizzard announced today. "The show is an important one for the European and global gaming community, and we’re going to miss meeting players in Cologne this year."
Gamescom is traditionally a more European-oriented event than E3—it's held in Cologne, Germany—but it's also been an important platform for Blizzard in previous years. Significant reveals over the years include the first post-release Overwatch map, animated shorts for Bastion and Mei, World of Warcraft expansions, and—many years ago—the first publicly-playable appearance of StarCraft 2: Heart of the Storm.
Blizzard said back in February—after a record year resulted in hundreds of layoffs at the company—that there would be no "major frontline releases" in 2019, which is the likely explanation for the Gamescom absence. With less to show, it's reasonable to assume that it's holding back what it's got for BlizzCon. But Blizzard also said that this isn't a permanent state of affairs: "We're looking forward to returning to the Gamescom floor in the future."