i would like to no as well.
Rocket League [PC/PS4]
Street Fighter V [PC/PS4]
Shadowrun [PC/360]
Are a few that come to mind. I know there are a bunch more if I take the time to google them.
Also, there's a lot of talk about cross platform play between XB1 and PC once the Windows 10 update on XB1 completely rolls out. I haven't looked into it much though. The point is, its been, and continues to be done. The question is why Sony and MS don't allow gamers to play against each other regardless of console. The answer has to be because as much as they pretend they don't care about console wars, they understand the intense brand loyalty gamers have, and will continue to capitalize on it so long as it continues to be financially profitable for them. Opening up cross platform play would mean most people would just go with the cheapest console, whereas now, you have fanboys that will get their favorite console regardless of the price, or lack of exclusives.