Star Trek: Picard is not exactly a sequel to Star Trek: The Next Generation, but it's not not that either. The cast of the new series Picard is mostly comprised of new faces to the Star Trek universe, besides the titular fearless leader, but includes many familiar characters from previous Trek incarnations that fans will be excited to see as well. Jean-Luc (Sir Patrick Stewart) may be engaging a new crew, but he'll be checking in with many old friends along the way.
Not every character from Star Trek: The Next Generation is returning in Picard, however. This show isn't about getting the gang back together. Both LeVar Burton and Wil Wheaton are notably absent from the announced cast, but there's always a chance they're being saved as a surprise for later in the season. But for now, we can rule out seeing Wesley or Geordi.
Some of the characters that are returning can shed light onto the various pieces of Star Trek canon that Picard is playing with in its metaphorical sandbox. Specifically, this series is going to be dealing with artificial intelligence, the Borg, and Romulans. The series kicks off with a mystery and if you want to start formulating theories, the cast of this show might be a good place to start.
Here's who we'll meet, and who's returning, in Star Trek: Picard.