In the preview for episode 49 of Dragon Ball Super, it appears that Black Goku manages to find a way to make it from Future Trunks' alternate timeline to the main timeline of Universe 7. And judging by the grim faces on Goku and Vegeta it appears that Future Trunks has filled them in on what's happened in his world and they look pretty pissed at Black Goku. Will Vegeta take the first shot at Black Goku to avenge his son or will Kakarot strike first at his evil doppelganger? And with both Goku and Vegeta ascending to the ranks of Supery Saiyan Blue, will Black Goku even stand a chance? If Future Trunks remained at the general level he was at during The Cell Games, it leaves the window open for Black Goku to be way stronger than Future Trunks but still pale in comparison to the new found power of the Super Saiyan Gods.
Dragon Ball Super Arcs
Battle of Gods arc | episodes 1-14
Resurrection of 'F' arc | episodes 15-27
Universe 6 arc | episodes 28-46
Future Trunks arc | episode 47-ongoing