Guardians 2 should have introduced her as another girl-child abducted / adopted by Thanos after he massacred her homeworld, and empowered the same way as Wanda and Pietro were, by experiments with the Mind Stone (which he possessed at the time, before lending it to Loki and losing it). A whole team of 'Daughters of Thanos,' some empowered, some cybernetically enhanced (like Nebula and Gamora), would have been more interesting, IMO, than those Black Order scrubs.
But that time has passed. I doubt they'd even bother, at this point, introducing Moondragon as Drax's daughter, since they've mostly given the family-metaphorical storylines to Quill and his dad, and Gamora and Nebula.