20% off at Macy’s using your Citibank Debit Card

So I have never shopped at Macy's – ever. And my Citibank AAdvantage Debit card stopped earning miles last year. But this email from Citibank sounds interesting:

Use your Citibank Debit Card to make an in-store purchase at Macy's on any day between May 1st and May 27th and get a 20% discount. It's just one more benefit of being a Citibank customer.

There are a number of Macy's coupons here – you may be able to stack them with the above coupon?