We still don't really know what happened to Xivu Arath and Savathun. Oryx's sisters. We can probably assume oryx consumed them to become The Final Shape but they could still be out there. And at the heart of that we have the worms, do they simply find another host or die? Other than that the cabal were sending out a transmission to some cabal commander, we don't know much about them but nobody ever wants to mess with them for some reason. But I like the idea of having something to do with the Traveler, it's inactive. Maybe we bring it back to life, not that it's dead but it's been running for a reason, maybe to find the other parts it's missing. Who knows...