When you look into all the lore about all the different enemies, then it makes sense as to why the Hive are the main enemy and why almost everything involves them. A Cabal raid is probably quite unlikely as there is much speculation that the Cabal home world has been destroyed. Also the Cabal that we encounter appear to be running from Oryx and have lost countless soldiers to His forces and being taken. It seems that there is still a Cabal high command and there could potentially be other planets occupied by the Cabal. But I'm guessing that the number of Cabal in the high command and on other planets and ships is rather low. The Cabal never retreat, never surrender, never give up. And the fact that the Cabal on Mars were on the run from Oryx shows just how powerful he was and that they could not defeat him. Although we defeated Oryx in his throne world, we had to become ascendant hive and use sword logic to become strong enough. The power we draw from the 'Sky' and the Traveler is immense, and by us defeating Oryx we have become incredibly more powerful. Siva was a formidable foe for us, a new enemy we don't fully understand or know how to defeat. We stoped the Fallen from creating more Siva by destroying the replication chamber, but we didn't destroy Siva itself. I think Siva will make a return but not necessarily as an enemy. Siva isn't evil, it only does what it is commanded to do. There is Siva in deep space and the Cabal could happen to come across it and find a way to use it for themselves thus becoming more powerful. If this were to happen I recon it would be the Psions that harness this power and not the Cabal. A Psion style raid could happen without Siva as well but I don't feel they are powerful enough to take on Guardians without some type of powerful weapon. If the Psions were to come across a great power, I think they would leave the Cabal behind. It seems that the Psions and Cabal have some sort of working relationship together. There is speculation that the Psions are prisoners or slaves to the Cabal, I don't think this is the case though, as they are already very powerful. They are the ones that pulled Phobos from its orbit and into Mars' atmosphere. If they have the ability to pull a Moon from its orbit then I feel they would not fear the Cabal. My theory is that the Cabal came across a planet they wanted and it was occupied by the Psions, who were currently at war with Oryx and the hive. Normally the Cabal would use an opportunity like this and attack both sides, who would be weakened by war, winning the planet for themselves. But given how powerful Oryx was, the Cabal saw their own destruction by his hand and thus formed a partnership with the powerful Psions to combat this common enemy. Oryx would have ultimately won the war, thus winning the planet, and the remaining Cabal and Psion forces fled, seeking refuge in our solar system, trying to build their forces up again to take on this foe. If this is the case then cause we destroyed Oryx, sword logic states that we are now more powerful that Oryx, which means the remaining Cabal forces would be no match for us. The taken will rise again as someone is yet to claim Oryx's old throne for themselves. We had the opportunity to claim the throne, but chose to serve the light ('Sky') instead. Oryx was one of the most powerful beings in the universe. He slaughtered Billions and wiped out countless spices to extinction, yet there seems to be one race that we know of who did not fear him or see him as a threat, and that is the 9. We know very little about the 9, but they are regarded as beings of great knowledge and power. You can hear the speaker say 'if only the 9 would help' which heavily implies that with the 9's help we could strike a crippling blow to the darkness, possibly ending the war once and for all. This then opens up new opportunity for new enemies. Who do the 9 fear? Who do they see as a foe? Will they require our help one day or will we see ourselves facing them in battle? Only time will tell guardians...