Foundation (AppleTV+)
Showrunner David S. Goyer: "We have through Season 4 fairly rigorously plotted out, and then if we can get beyond Season 4, we’ve got some big tentpoles that we know we’re riding towards, and kind of 5, 6, 7 and 8 I know where most of the characters end and whether that be in Season 4 or Season 6, we’ll move it down or up the scale depending on how many seasons we get."
Source (nice spoilery interview): https://www.thewrap.com/foundation-season-2-finale-ending-explained/