Microsoft's Mixer could come to PlayStation 4.

The Beam rebrand and exciting features happened yesterday with 4K support just in time for Xbox E3, co-streaming allowing you to broadcast up to four streams all on one screen, meaning a full co-op squad of Gears of War can now be shown on a single screen for a much deeper immersion into the team’s gameplay, and the news stream is called Channel One and will feature event announcements, esports updates, and various other breaking news.
A fan spoke to Phil Spencer saying Head of Xbox was open to having Mixer on other platforms including its rival Playstation to which, Phil Spencer replied with “Yep” giving us an impression Microsoft is willing to share its Twitch competitor with Playstation.

Not much has been said by Phil regarding this matter, but until we get more news be sure to stick around.