Sadly I could see them going the WiFi route. Not Nate Grey, as he’s not Cable and has no T-O virus. But could see a scenario where, after the adult Cable we’ve already met from Season 1 helps them beat Bastion, he departs for his future again and his younger self shows up right after and stays in the present for awhile. To spend some time amongst his parents and the X-men to train for his fight against Apocalypse and the High Lords in the future. Or something like that.
I would hate it, but I’m sure there are many who would enjoy that.