It's hard to say these days. When Christopher Cantwell's Doctor Doom series was promoted the article from Marvel said it was an ongoing. It never had that delimiter on it that is was say 1 of 10 issues (#10 was the final issue) Then the pandemic came along in March 2020 and production stopped on a lot of things. When it finally returned to in the fall, it was to wind up the first arc and that was the end of it. Cantwell has stated he had a second one planned but I guess they decided to just end it instead. Sales weren't bad. They were passable but then it was hard to find any published sales figures after March of that year.