Trusted Traveler is what you could call the list that Pre-Check vets you against, so Pre-Check is really just Trusted Traveler. Yes, Global Entry is only for returning to the US (you couldn't imagine it would be more, it is a US-run program), but it does also enter you into the Trusted Traveler program. The only reason I know this is a recent client of mine is a travel industry expert who spent time clarifying the programs and how they interact with each other. Their frugal recommendation is, if you travel outside the US, the smart move is to do Global Entry, more bang for your dollar.