Can someone fill me in though, was Cable in the original show? Did he know of his lineage, or is this only now coming up?
Cable did appear repeatedly in the original series, but his backstory was never addressed. In fact, in the first season (which I believe had different writers and used some characters in weird ways), he was used as a present-day mercenary, but later seasons depicted him more accurately as a time traveler without explaining the discrepancy -- and without revealing his parentage, though I think it was hinted at vaguely once or twice.