I had Black Ops 1 and the Moon map pack for Xbox 360 and I recently downloaded it onto my Xbox One. However, my DLC did not download. I checked the store to see if it would let me just download it but it makes me pay. Is it not possible to download the DLC I already paid for?
I haven't tried out the previous purchases on the Xbox one yet. But is it the same as the 360. Where you can go check your purchase history?– Doc306Apr 16, 2017 at 18:54
If that's a possibility. Then you should be able to download from that source. Otherwise you could remove your credit card, then try and download the dlc. More than likely it will say that "you already own this item, would you like to download it again?"– Doc306Apr 16, 2017 at 18:57
Similar to the My Games & Apps menu that shows you all content installed on your XB1, you can see what content you have installed (and ready to install) on a per-game basis.
To do this, press Start on your backwards-compatible game's tile (on the Home screen or in your game library), and click Manage.
This should show a screen similar to your games library, but the "Installed" and "Ready to Install" should just be for your game. Any DLC you own should be in the Ready To Install category, as in the screenshot below.
1It's unfortunate that this is the only way to actually do it. I was playing the Mass Effect trilogy and thought to myself "I know I have all of the DLCs. Where are they?". Sure enough, had to do some research and found out that I had to do it this way^^^. Mar 2, 2018 at 15:36