You'll want to build an "Assignment" report and not a "Task" report. You can't easily delineate the assignees of a task on a Task-Level report (without doing something complicated with a calculation inside of a list).
If you build an "Assignment" report you can display both the Task >> Status (which is the status of the task itself) as well as the Assignment >> Status (which is the status of the individual).
For example, if someone is done with their part of a task, but the task itself is not yet complete (other people are still working on it), on the report, that user's assignment would show an Assignment >> Status of "Done" and the Task >> Status would still show "In Progress" (or whatever Status it's still in).