If he's from the future, why doesn't he go back in time and tell himself to stop being such a tool? 
History
The history of this Cable seemingly followed the same path of his Earth-616 counterpart's, except this Nathan Summers has not been freed of the Techno-Organic Virus yet.
Cable arrived to Genosha in the present, where his old partner Deadpool was trying to kill Mr. Sinister. Cable wanted to warn Wade about his important role in stopping the evil mutant, but the regenerative mercenary decided to shoot himself in the head in order to stop himself from hearing Cable's "dire warning-from-the-future crap."
Cable left a note stabbed in Deadpool's chest for when he woke up, where he ordered Wade to go to the north end of the city. And in order to ensure Deadpool would do what he wanted, Summers mentioned after going to his destiny, Wade would find a large breasted naked woman who claimed to be his greatest fan. The plan worked as Deadpool met Cable, but Wade's delusions made him believe Cable was his fan, although he immediately came to his senses. Summers told Deadpool they would need to go to Magneto's old citadel, and that they didn't need to worry about a security tower where Mr. Sinister was. Deadpool abruptly made his way to the top of the tower and killed Sinister, who was just a clone of the real Sinister, as Cable told Wade.
Nathan proceeded to make a plan to get to the citadel, where it would take days walking to get there. Deadpool convinced Summers to modify a Sentinel boot to make it fly, and left before Cable could get on board. After Deadpool rescued Rogue (who was along with the X-Men also trying to stop Sinister) from Blockbuster, the mercenary accidentally fell to a hidden catacomb.
There he met Cable once more, who was stopping Sinister's goons from exhuming mutant corpses for their master's plan. Summers continued to handle Sinister's army of clones while Deadpool helped Death to free some spirits.
After Deadpool finally killed the real Sinister, Cable briefly appeared to congratulate him.[1]