Over on the Twitter, Jackson has confirmed the news that Venture Bros. was cancelled, which includes the in-progress season eight:

Unfortunately, it’s true: #VentureBros has been canceled. We got the highly disappointing news a few months ago, while we were writing what would have been season 8. We thank you, our amazing fans, for 17 years of your kind (and patient) attention. And, as always, We Love You. — Jackson Publick (@jacksonpublick) September 7, 2020

However, Adult Swim has responded to the outcry with some small glimmer of hope:

We also want more Venture Bros. and have been working with Jackson and Doc to find another way to continue the Venture Bros. story. — adultswim (@adultswim) September 8, 2020

What this may turn into remains to be seen of course, but it's possible the the show at least gets a proper sendoff in some format or another. Stay tuned!