In the gaming world, a "repack" usually refers to a highly compressed version of a game. While these are popular for single-player titles,

If you find a "Portable Overwatch" that claims to work offline or includes "all skins unlocked" without connecting to the internet, it is likely How to Create Your Own Portable Overwatch

Overwatch is inextricably tied to Blizzard’s Battle.net launcher. The launcher handles authentication, patches, and anti-cheat (Warden). A "portable" repack would need to emulate or bypass:

Five new faces joined the roster this February, including the highly anticipated Jeteck Cat . Conquest Mode: A new meta-event where you choose between or Talon to battle for global territory.