Heroes of the Storm is not dead. Although development has slowed down considerably (there have only been a few new characters out in 2019 compared to the usual cadence of "a ton") and the esports arm has been shut down, there's still a team working on the game, doling out events and balance patches.
A lot of lapsed players have a huge reason to come back soon, too, as Deathwing is joining the roster. Although information is very slim right now (one of his heroics involves diving in like when he caused the Cataclysm event in World of Warcraft) and more is coming at BlizzCon, Blizzard revealed via Twitch that Deathwing will be added to the game soon. Initially we got a Smash Bros.-esque "fakeout" with the Brightwing skin, but nope: there's Deathwing, the giant ass dragon, with an in-game-and-not-April-Fools character model.
We do have some details though. Deathwing is going to have two forms due to the fact that he's so powerful (he can fly up in the air and slam down), and cannot be targeted or healed by teammates. Heroes is known for mixing things up with weird characters (including one that works like an RTS game or another that's operated by two players), so this is right in their wheelhouse, and Deathwing is the one to warrant such an experiment. Expect a PTR period following BlizzCon and the full reveal, where he will be playable on the showfloor. You can catch some gameplay on the Heroes Twitch channel too.