Claimed to be descendants, etc. It was something of a fashion among nationalist Hungarians.
Huns have no known connection with Magyars, the nomadic peoples who were the ancestors of the Hungarians.
Similar claims with just as sparse or non-existent basis include the Poles who used to claim descent from the ancient Sarmatians.
Well the truth of the claim aside; I still wonder what the Hungarians thought of us demonizing the Germans by calling them “Huns” as the Hungarians (correctly or not) revere the Huns as their forefathers.