I built a GitHub app that checks for uncompleted checkboxes within pull request comments and blocks the merge if found.
This allows you to treat checkboxes as to-do’s and:
* Open pull requests with a to-do list template -> make sure all steps are completed before merging
* Leave to-do reminders for yourself as you work on a pull request
* Leave to-do reminders for someone else as part of your code review
Especially useful for large PRs with collapsed comments.