Is ONE PIECE episode 1056 filler?
Canon No, episode 1056 of ONE PIECE is canon.
#1056
A Countercharge! Law and Kid's Return-Attack Combination
逆襲! ローとキッドの反撃同盟
Aired 2 Apr 2023
Mochibayo compiled this list from MyAnimeList's labels, because MyAnimeList's episode data is not reaching us at the moment.