WARNING: The following contains spoilers for Cable #11 by Gerry Duggan, Phil Noto & VC's Jow Sabino, on sale now.
Despite the presence of the younger version of Cable on Krakoa and his recent work alongside the X-Men, the time has finally come for the original older version of the character to be restored in Cable #11. Thanks to the resurrection protocols of Krakoa, Cable is revived to to work alongside his old allies and his younger counterpart against Stryfe. But as a part of his resurrection, it's ensured that he continues to be infected with the Techno-Organic Virus -- and there are actually some good reasons for that.
The Techno-Organic Virus is one of the deadliest biological weapons in the Marvel Universe. The disease is potent and powerful, corrupting organic matter and converting it into living technology. The T-O Virus seeks to fully convert those it infects, and seeks to spread to more and more life forms. Befitting the mysterious origins of the disease, there is no confirmed cure for the virus -- however, a powerful enough psionic could use their abilities to halt the spread of the disease. This was the fate of Nathan Summers, aka Cable. Infected with the T-O Virus while an infant by Apocalypse, Cyclops was forced to hand his son over to the time-traveling Sister Askani to have any chance of saving his son.
Although Nathan was already infected and unable to stop it from spreading across one of his arms and onto his face, he was able to train in the use of his telekinesis and telepathy to halt any further spread. Cable has since grown accustomed to the disease being a part of his life and has even embraced it. When he's revived by the Five on Krakoa in Cable #11, Hope even ensures he's revived with the virus intact -- nominally because he has control over it and because he wants to continue to study the disease. This way, he could potentially learn how to counter it, cure it if someone else were to be infected -- or even weaponize it.
However, there might be an additional reason Cable has gotten used to the effect of the virus on his system. Because Cable has always had to push some of his power towards holding the T-O Virus at bay, he's never faced the threat of being overwhelmed by his abilities -- which almost happened to Nate Grey. Cable's equivalent from the Age of Apocalypse reality, Nate was a genetically crafted clone of Cyclops and Jean Grey made by Mister Sinister. However, he was never infected with the T-O Virus and instead learned to embrace the sheer potential of his psionic powers, especially after coming to Earth-616. Without those restraints, Nate was considered an Omega-Level mutant for a time -- and even theorized to be capable of standing up to the likes of the Sentry or the Phoenix Force.
However, the lack of a T-O virus to restrain his powers resulted in his body effectively becoming a psionic time-bomb. Due to the sheer amount of power he possessed, Moira MacTaggert hypothesized that he wouldn't live past his twenty-first birthday in his current state. Eventually, Nate's powers would need to be siphoned off somewhat, allowing him to survive -- and when they were fully restored, he was forced to learn a greater deal of control over them. The T-O Virus distracting Cable and keeping his powers in check may have actually saved his life, as it meant there was a way for some of that excess energy to be directed and contained instead of causing him to ever overload.
When the T-O Virus was briefly rendered inert, Cable gained powers on the same level as Nate Grey and used them to create the island of Providence -- and eventually even allowed him to go head-to-head with the cosmic-powered Silver Surfer. However, without the T-O Virus, it's unlikely Cable would have survived long with his powers unchecked. With those mental blocks in place due to the necessity of the T-O Virus, Cable gained a level of precision with his powers and how to utilize his wits and weapons to win battles. While it may seem like a hindrance at first, there's actually plenty of reason for Cable to still want -- and moreover, need -- the T-O Virus.