Like Bran, Jojen had the power to see the past, present and future in visions. Jojen knew he would not survive the journey, but helped Bran anyway because he believed the future Three-Eyed Raven would be important in the fight against the Night King (Bran gave Arya the knife she used to slay him, so he wasn’t wrong).
Meera, a skilled fighter pictured above, stuck with Bran even after her brother’s death, helping to keep him safe until they made it back to Winterfell. She had a tense goodbye with a detached Bran, who no longer conveyed much human emotion after becoming the Three-Eyed Raven. So the last we see of her is before the Night King and his army make their way down to Winterfell.
Jojen and Meera were also the children of Howland Reed. Howland saved Ned Stark’s life during Robert’s rebellion, and was a part of the mission to try to rescue Lyanna (the mission on which Ned learned the truth of his sister’s kidnapping). That’s two generations of Starks that owe their lives to two generations of Reeds. But we never learn whether Meera and her family survived the war between humanity and the army of the dead.