Five years ago, Blizzard said that it had "no plans" for cross-platform play in Overwatch, warning that "mixing mouse/keyboard and controller can have balance and competitive issues." Two years later, attitudes had shifted somewhat, and game director Jeff Kaplan said that he was "hoping for more cross-platform opportunities," to help "bring players together"—although there was still no actual movement on that front.
Very soon, that will change. In a surprise announcement today, Blizzard said that a crossplay beta test is coming soon to Overwatch that will allow players on all platforms—PC, PlayStation, Xbox, and Nintendo Switch—to group up and play together. To take part, download the latest Battle.net update (or make an account if you don't already have one), then go into the settings and link your console accounts through it. The update has also merged friends lists from different territories, so you'll be able to play with people in other parts of the world without having to switch regions first. (China is excluded from this, however, and will remain its own separate region.)
The announcement of the Overwatch crossplay beta also effectively confirms that it will be a feature in Overwatch 2 as well. Blizzard recently revealed some big PvP changes coming in Overwatch 2, including a reduction in match size from 6v6 to 5v5 and restrictions in team composition, but crossplay support had not yet been confirmed. Now we know!
As an added bonus, everyone who links their accounts and logs into Overwatch by the end of the year will be given a Golden Loot Box to mark the launch of the crossplay beta. A rollout date hasn't been set yet, but you can find out more the Overwatch crossplay FAQ.