Do you mean the version of Outlook that comes with Microsoft Office and runs on your computer, or a web-based version of Outlook? The version of Outlook that installs on your computer can work with supplemental local files, so you could move your old mail from Thunderbird into Outlook (although I have no idea what the steps are for that). Cloud-based email interfaces might not be able to import old mail, in which case you still could view it in Thunderbird, but it would be much less convenient.