Why is my task list not displaying all tasks in a subsite in SharePoint?

1. Check if the tasks in the subsite have been marked as completed.
2. Check if there is a filter applied to the task list in the subsite.
3. Verify if the user has correct permissions access to the subsite.
4. Make sure the user has correct permissions to the task list in the subsite.
5. Verify the date range for the task list.