Said it before, I'll say it again.
I believe CABAL used the generated ion particle interference that crippled GDI communication with the Philadelphia to launch his true core, potentially cloaked using Nod's stealth technology, offworld as the combined forces of GDI and Nod were busy battling against a sort of remote controlled copy AI of CABAL himself, destroying yet another false core and eliminating CABAL's terran ability to further cause conflict, as he had already fled.
Most likely, CABAL will come out in the expansion, though I doubt he will be a playable faction in all honestly, as it would basically boil down to cloned human cell-culture cyborgs of various sizes and shapes, ways to harvest them, and tiberium mutations. So, while it might be possible for him to constitute a fourth faction, it may be too similar to the as-of-yet-unnamed Aliens to really recessitate it, or be too close to a 'Yuri' faction depending on how they expand it. But there's still the hope.
Also, CABAL as a faction could easily resemble the Imperium Shadowhand from Dark Reign.
