[Little Pig]

If the time skip is big enough, this might put to rest the rumors that Deckard was a replicant himself (something that was implied was the case in the first movie), unless he was some kind of custom job that didn’t have the artificially-short lifespan; given that we don’t see Rachel in the trailer, she may have already “died”, and it’s unlikely that Tyrell would have given Deckard an extended life but not her.

[MrEdd]

If the time skip is short (given how much Harrison Ford has aged) then they can show Deckard was a replicant.

[Army Air Corps]

given that we don’t see Rachel in the trailer,

Have you seen the director's cut?

[Boogieman]

“it’s unlikely that Tyrell would have given Deckard an extended life but not her”

Tyrell did give Rachael an extended lifespan. She may have died of unnatural causes though, especially since she was probably being hunted down.