And Delta is providing an ecredit for any flights booked by May 31 which is good through May, 2022...You may be able to press for a refund but it's a more complicated process...
Looks like we will be bailing out the major airlines again...

"Travel changes you. As you move through this life and this world you change things slightly, you leave marks behind, however small. And in return, life — and travel — leaves marks on you.”
-Anthony Bourdain