TRUE VAULT HUNTER MODE
As part of the end game content for Borderlands 3 you will unlock a new mode called true vault hunter.

When you’re ready for the next step up in difficulty, beating the story campaign also unlocks True Vault Hunter Mode, which is Borderlands 3’s take on New Game+.
As you’d expect from a challenge befitting a True Vault Hunter, the enemies will be tougher and the loot will be better compared to your Normal mode conquests.
Your character’s mission progress is unique to Normal or True Vault Hunter playthroughs, but your Vault Hunters’ stats and equipment are shared across both modes.