With Overwatch 2 on the way, Blizzard offers an Account merge FAQ to explain how players can merge multiple Overwatch accounts to carry over progression into Overwatch 2. Word is all players will need a battle.net account to play Overwatch 2 regardless of platform. For players on PC, progress will automatically carry over, but any console accounts will still need to be merged. Players only get one shot at this process, so care should be taken. Here's the overview:

With the launch of cross-progression, players can merge multiple Overwatch accounts to carry progression and in-game cosmetics into Overwatch 2 on a single profile. Starting August 16, every player with a linked console account will be prompted at login to identify, select, and confirm the accounts you want to merge. Once you approve, we will prepare your accounts to be merged during the release of Overwatch 2.

All players will need a battle.net account to play Overwatch 2 regardless of platform. Progress from linked console accounts will be stored on your battle.net account, which will share in-game cosmetics and progress across the linked accounts.

There will be one opportunity to merge console accounts, so make sure you double-check which accounts you are merging before you confirm!