Microsoft today announced that Microsoft To-Do integration is coming to Outlook.com experience next month. As part of this integration, Microsoft has added a new Tasks pane that can be used with both Mail and Calendar apps.
This Tasks pane will allow you to create a task by dragging and dropping an email into your Tasks pane or easily schedule a task by dragging it from the Tasks pane to your calendar. You can access the created tasks from Microsoft To-Do apps across platforms.
You can try out this feature from December 2018.