Yes, you can refer to a Bitbucket Cloud issues, requests, and users directly from a comment an issue or a commit message. When you create a reference, saving the comment (or issue) causes Bitbucket to automatically link to that object. You can also mention an individual account or workspace — even insert an emoji. For items that are repository-specific, such as issues, pull requests, and commits, references to Bitbucket objects always refer to the current repository.
To see specific examples of linking to Bitbucket Objects from Comments and Commit Messages, refer to Mark up comments.