A final raid in destiny! The city is under attack by hive, cabal, vex, and fallen. The city is divided into four major parts and each belongs to different enemies which contains a boss that will, over time reach the traveler. This raid would be perfect because there would be four bosses that represent each enemy. (i.e. Cabal boss for cabal.) This would truly prove worthy for any guardian and there is no other objection than reach the city, stop the enemy and save the traveler.
Sorry man but according to lore cabal have no interest in earth or humans. And from what I remember the are after the vex.
It would be cool if because we killed part of the darkness that the vex worship the cabal help us.