Brent Spiner's return as Data in Star Trek: Picard was an SDCC surprise no one saw coming, mostly because (2002 spoiler alert!) Data died in the film Star Trek: Nemesis. And while being dead on Star Trek has never been a huge impediment and in fact, for many characters — from Spock to Dr. Culber — coming back from the dead is a sci-fi rite of passage, resurrecting Data is a bit more tricky.
https://www.syfy.com/syfywire/7-ways-star-trek-picard-could-bring-data-back-to-life