every commit to an existing pull request will create a new set of ci/cd jobs. but normally we just wanted to test the branch's latest version. Any unfinished previous testing jobs could be cancelled immediately when a pull request updated. This will release self-hosted machine resources and improve the overall dev efficiency

perhaps could use this https://github.com/styfle/cancel-workflow-action

mainly for the per PR self-hosted job: https://github.com/Project-MONAI/MONAI/blob/master/.github/workflows/pythonapp.yml#L154