Alongside Blizzard's reveal of an Overwatch sequel, it was announced that Overwatch 2 will be cross-compatible with the first game.
Players who currently own Overwatch will have the ability to transfer all cosmetics earned to the sequel. This includes emotes, character skins, voice lines, and etc. Players will be able to queue into multiplayer matches with Overwatch 2 players on the same arena/ maps. Jeff Kaplan made it aware that Overwatch will continue to be supported even after Overwatch 2 releases.
Many changes to Overwatch 2 include a story mode, new PvE modes, improved/ new character models, a level-up system, and many more modes and features that will only be exclusive to Overwatch 2. However, many fans and critics don't fully see this as enough to warrant a "sequel" but instead see Overwatch 2 more as an expansion to the original.
In other news, Overwatch has reached a player base of 50 million since its original release back in May of 2016 and it just saw a release on the Nintendo Switch last month in October of 2019.