https://screenrant.com/star-trek-picard-season-3-ds9-changeling-clues/

The Changelings from DS9 are back in Star Trek: Picard season 3, and the first 3 episodes dropped several clues about the shapeshifting villains.

Picard's Odo Easter Egg Answers A Big DS9 Finale Question (https://screenrant.com/star-trek-picard-season-3-odo-ds9-answer/)

Odo was last seen in Star Trek: Deep Space Nine's series finale, but the heroic Changeling is crucial to Star Trek: Picard season 3's story.