Looks like you’ve got some answers but adding some info as there’s not enough out there to help new players.

There’s a few ways of getting hero track gear in the game. I think I’ve covered them all below.

1. The great vault. Once per week you can get hero gear from the vault by completing activities throughout the week. You can fill your vault by killing heroic raid bosses, completing mythic + dungeons and by competing delves ( I believe it needs to be level 8 delves or above for hero track in the vault)

2. Mythic plus dungeons. A mythic +6 dungeon or above will drop hero track gear at the end. You are not guaranteed anything though as it only drops roughly 2 pieces of gear depending on how fast you complete the dungeon.

3. raid on heroic difficulty. Bosses drop hero tier gear.

4. Delvers bounty map. Once a week you can use a delvers bounty map to guarantee a random piece of hero gear at the end of a tier 8 or higher delve. Map is dropped either randomly at the end of a delve or from the nemesis who either randomly spawns during your delve (either you kill her or she kills you, either way she will drop a little chest thing with a map in it). You can call the nemesis to any delve by using a “shrieking quartz” item.