The first three seasons of "Haikyuu!!" came out promptly in 2014, 2015, and 2016. Then, there was a huge gap between the third and fourth seasons, and the fourth season itself was not announced until late 2018, per Crunchyroll. It aired split in two segments (or cours) from January to April 2020, then October to December 2020. It's now been several months since the last episode of Season 4 aired on Crunchyroll, and there's no word yet on whether a Season 5 is coming from Production I.G. 

However, in December, following the last episode's transmission via Crunchyroll, the English-language Haikyu!! Twitter account put out a message thanking the "anime team" for their hard work, and adding, "Looking forward to the continuation!" This seems to imply it's expecting a fifth season to arrive at some point. It's difficult to know when this might happen, however, and the fact that the show had such a long hiatus between the third and fourth seasons makes fans worried that there will be another delay before official news comes about Season 5. Monsters & Critics noted that experts believed the previous delay was due to in-house factors, including waiting for key staff members to complete other projects. 

Extrapolating from the December 2018 renewal and the January 2020 airdate of Season 4, it can be expected that "Haikyuu!" has a one-year production cycle, which means that whenever Season 5 is actually announced, the show will probably return (possibly in a split-cour format, again), 12-13 months after that. That's probably not the best news for fans, but hey — at least the anime theme song was played at the Tokyo Olympics during the volleyball event. The property remains relevant.