My estimated refund date was 3/22/20, but I have yet to receive my refund. Why is that?

The IRS issues most refunds in about 21 days, although some returns take more time to review. Turbotax gives an estimated date based on the IRS's 21 day timeframe. So it all depends on the IRS and how fast your tax return moves along in the system. TurboTax does not receive any updates from the IRS. Therefore, I would not worry about the estimated dates.

If your return shows "processing" on the IRS  Where’s My Federal Refund? site, during this time, the government reviews your refund. During the review process, they look for math errors on your return (extremely rare in TurboTax) and they also check if you owe back taxes, unpaid child support, or other debts. 

If they need to make any corrections, they may offset (reduce) your refund. In some cases, the correction might even increase your refund.

Once that part's done, the government approves your refund, which means it's ready to be deposited or sent.  At that point the IRS site will update with a direct deposit date. 

The general timeline of e-filed returns is: Transmission > Acceptance > Processing > Approval > Refund.

Continue to monitor the IRS Where’s My Federal Refund? site for updates. Updates are made daily, usually overnight. You may also download the IRS2Go app to check your Federal refund status.

Please see the links below, for additional information:

• Where's My Tax Refund? The IRS Refund Timetable Explained
• IRS Tax Season Refund Frequently Asked Questions
• What if my IRS refund is taking longer than 21 days? - TurboTax Support Video