Ask HN: How are pull requests integrated in a repo with high commit frequency?

So let's assume we open a pull request, merged current main into our feature branch and are running tests. The full acceptance test suite takes 5 minutes to complete. Meanwhile, in those 5 minutes, 10 other commits have been made. If we merge now, we can't be sure that we won't break stuff right?

So after merging the pull request, are you supposed to perform another set of regression tests? Hard to find info about that