Overwatch is FINALLY getting cross-play!
FAQ about Crossplay here.
TL

W:
Cross-progression will not be available "at launch."
Console players will need to link a Battle.net account upon the cross-play patch.
Competitive cross-play will be limited to consoles; PC players will have their own matchmaking pool.
If you have a party of console+PC, you will be matched with the PC matchmaking pool.
Subsequently, aim assist would be turned off when you match with PC players.
PC players cannot disable cross-play.
It's about time; now work on cross-progression.