I got an email about it. I canceled HBO a few weeks ago.
Fine Print in the email
"
*HBO/Cinemax $15.99/mo for 12 Months Offer: Offer ends 12/31/17. Customers who subscribe to both HBO and Cinemax, with at least one (1) being a new subscription, will receive a $15/mo. bill credit for 12 months. Credit may take 1 to 5 weeks to to appear on customer's bill. Offer available to residential DIRECTV customers with accounts in good standing as determined by DIRECTV that are not currently subscribe to HBO or Cinemax. Programming & pricing subject to change. Cannot be combined with any other HBO or Cinemax promotional offers. Conditions apply. Call 1-800-531-5000 to order. "