Up until now Microsoft have not allowed cross play on the Xbox One, a policy that actually made Square Enix decide not to release Final Fantasy XIV on the Xbox One a while ago, but that is about to change.
Developers who make games for Xbox One and Windows 10 will be able to support cross-network play, provided the other networks are also participating. For those who don’t know, cross-network play allows people to play together online on different platforms. You can play a game on your PS4 and be playing with someone who is currently on PC. Now Xbox is in the mix.
Rocket League will be among the first games to support this with Microsoft saying there is an “open invitation for other networks to participate as well”. The quote seems aimed at Sony, the company behind the other big console network, though Sony have supported cross network play for quite a few games, including Rocket League.
Rocket League is currently available on Xbox One, PS4 and PC, with the cross-network play coming later in the spring.