Despite all of the action in Salvation’s plot, there’s only really two important beats it contributes to its ultimately unfinished story: John Connor meets and save a young Kyle Reese (Anton Yelchin), ensuring his own existence, and John is ultimately given Marcus’ heart to ensure he lives to fight on to either the end of the war and/or his death in 2032 at the hands of a rogue T-800.
This all eventually leads to Terminator: Salvation’s piece of the timeline, as we catch back up with an older and battle hardened John (Christian Bale) and Katherine (Bryce Dallas Howard) in the then-far flung year of 2018.