This year's combined 21st and 22nd issue of Shueisha's Weekly Shonen Jump magazine revealed on Monday that Yūki Tabata's Black Clover manga will go on hiatus for about three months starting with the next issue so that Tabata can prepare for a new arc for the manga. Tabata discussed the matter with the editorial department, and they all made this decision so that this would also give Tabata time to rest. Weekly Shonen Jump will reveal at a later date exactly when the manga will return.
Tabata specified in his comment in the magazine the new arc would indeed be the "final arc" of the manga (the wording used could also be translated as "final saga"). He added that while he himself had planned to not take a break, after discussion with the editorial team, they decided this extended rest would give him time to write the manuscripts for the final arc/saga.
Tabata launched Black Clover in Weekly Shonen Jump in February 2015. Viz Media is publishing the manga digitally and in print, and Shueisha's MANGA Plus service is also publishing the manga digitally. The manga had more than 15 million copies in circulation worldwide as of May 2021.
The manga's anime adaptation premiered in Japan in October 2017. The show was originally listed with 51 episodes, but it continued into a new season with episode 52 in October 2018, and continued on again into a new season in October 2019. The show went on hiatus starting in April 2020 due to the effects of the spread of the new coronavirus disease (COVID-19) on the production, and resumed in July 2020 with episode 133. The show aired its 170th and final episode in March 2021.
Source: Weekly Shonen Jump combined issue 21/22