Warning: contains spoilers for X-Men #19!
While Wolverine and her unkillable X-Men team have finally escaped from the Vault, their mission to gather intelligence on its fearsome citizens came with a tragic cost, and yet one which may have a final twist that most fans missed. Recently, the younger Wolverine, Laura Kinney, and mutants Synch and Darwin infiltrated the Vault - a city-sized laboratory in which time is artificially manipulated to create a futuristic race of enhanced humans intended to supplant mutantkind. Unfortunately, they were detected, and ended up trapped inside for what felt like months to those on the outside, but centuries for Wolverine's team.
The new mutant nation of Krakoa has a complex system by which dead mutants can be resurrected, but this method of 'escaping' the Vault wasn't open to Wolverine's team. First, because it would render their mission pointless - mutants are reborn with only the memories from their last telepathic back-up, so no memories of the Vault could be transferred until they broke out and made contact with Charles Xavier. Second, because Krakoa has strict laws about resurrection. Mutants must be confirmed dead before they're eligible, or else the mutant nation's protocols - which are basically a telepathically-enhanced form of cloning - would risk creating duplicates of mutants who are still alive.
Wolverine's team therefore needed to first learn everything they could about the Vault, then get free so the information could be shared with Krakoa. Sadly, though the team were chosen for powers that would keep them alive, escape was impossible was centuries. During that time, team members Synch and Wolverine fell in love, separated when Wolverine was captured, only for Synch to stage a daring rescue. Having learned that teammate Darwin was being used to create a new, deadly generation of the Children of the Vault, Wolverine and Synch made a final breakout attempt. Ultimately, Laura stayed back to buy time, while Synch was able to get in range of Charles Xavier's powers. Heartbreakingly, that means that while Synch was reborn with the memories of his relationship with Laura, she retained only the backed-up memories from before the mission, now regarding the man she grew old with a stranger.
Thankfully, X-Men #19 from Jonathan Hickman and Mahmud A. Asrar ends on a note of hope. Laura may not remember her centuries with Synch, but she quickly repeats a phrase and gesture from their very first day in the Vault, making it clear that while the woman Synch knew is gone, there's still a chance he and Wolverine can forge a new version of their bond. Except... the original Laura may not be gone.
Synch and Laura escaped by passing through an energy field that stripped them of their powers. That meant that when Laura faced down the Children of the Vault, she had no way of surviving... unless they wanted her to. While they chase down and kill Synch (thankfully, right after he makes contact with Charles Xavier), Laura's death isn't shown, but rather assumed from her perilous final stand. That leaves the possibility that the Wolverine with whom Synch was trapped for centuries is still alive as a prisoner of the Vault, while the young, reborn Wolverine is exactly the kind of duplicate that the X-Men's protocols are intended to prevent.
Krakoa takes confirmation of death seriously, and usually sends the X-Factor team to investigate borderline cases. But sent on a top-secret mission that cost them lifetimes of suffering, Wolverine's team aren't subject to the same scrutiny. It's possible that Synch's partner, the woman who redefined his understanding of love, is still being held prisoner while he attempts to build a life with her duplicate - something that could prove especially traumatic for Laura, who until recently believed herself to be a knock-off clone of the original Wolverine.
There's no way to know whether the older version of Laura is still alive, perhaps kept as a bargaining chip or source of intelligence by the Children of the Vault. What is known is that this already tragic romance may have just set up a final twist of the knife. Synch and Wolverine's relationship is already a tragic romance, but don't be surprised if X-Men comics choose to double down in future with the return of the original Laura.