(1) Automatically cancel a review when the associated pull request is merged.
There are some on our team who are hesitant to add a code review tool because they believe that anything beyond the GitHub tool is too much overhead. After going from Collaborator to GitHub when I switched companies, I find I'm unable to do effective reviews, which is why we're going down the path of evaluating tools. I foresee a lot of reviews being created for 3-line changes and going stale. It would be nice if they could just be cancelled when the PR is completed or cancelled.
(2) Merge PR and Delete branch when a review is completed.
Some of the team dislikes jumping between tools, and don't want to have to click on the link to GitHub and then close it there.