Is ONE PIECE episode 1059 filler?
Canon No, episode 1059 of ONE PIECE is canon.
#1059
Zoro Faces Adversity: A Monster! King the Wildfire
逆境のゾロ 怪物！火災のキング
Aired 23 Apr 2023
Mochibayo compiled this list from MyAnimeList's labels, because MyAnimeList's episode data is not reaching us at the moment.