This was surprising news because the series had already been renewed for a sixth season. The URL is a little misleading since the show wasn't cancelled, it was the creators' decision to stop after this season, mainly so they could go on to other projects. CBC would probably have happily had the show on as long as they wanted to do it. (Funny Canadian sitcoms are a rare breed.)
The tweets from Simu Liu, who plays Jung (the son) on the show, indicate that the decision took the cast by surprise as well.
https://twitter.com/SimuLiu/status/1369017904352665602
I don't believe he's on the show this year (this season is part of my DVR backlog), but was hoping to return for Season 6, with the idea that his character would reconcile with Appa, the father. A movie or special where that happens would be a good way to wrap the series up.
John