I don't see any buds on my hydrangea this year, what happened?

At some time were they pruned?

Here is an article that might be helpful - http://thedailysouth.southernliving.com/2012/06/21/why-your-hydrangea-didnt-bloom/ - good luck

Some flowers, such as hydrangeas, bloom on last year's stems. If u over pruned AFTER your flowers bloomed last year, you removed all of this year's buds. Never fear. They will bloom again next year!

Did you have a sudden frost after the leaves started to emerge?

Not sure, it is at our vacation home so we weren't there much this winter. Anything is possible in Cape Cod

I believe the drought had so much effect on my crepe myrtles last year..and it definitely had an effect on my hydrangea and my Mothers too...probably will correct in a year or so with good rain, I think.

https://thistlewoodfarms.com/how-to-make-your-hydrangeas-bloom/

https://www.gardenguides.com/84033-make-hydrangeas-bloom.html

http://www.millionplants.com/advice/wont-hydrangea-bloom/

https://www.thisoldhouse.com/ideas/5-tips-growing-gorgeous-hydrangeas