Cross platform connectivity is an extremely beneficial feature that we value a lot. It allows for better matchmaking, predominantly on lower playercount hours and countries.
However, it is both a technical and bureaucratic challenge because platform holders are very protective of the features you can include in the game as well of the network technology to use. Some of these permissions are granted on a case by case basis and are still under discussion, so we can't realistically inform of when these features would be coming.
Cross-platform between Steam and PS4 is already working live, as well as cross-platform between Windows 10 and Xbox. We're working hard to include further cross-platform connectivity.