Well you guys go back to backwards compatibility now that Activision is part of Microsoft...

there is no information about when and how the Activision catalog will be handled in regards to game pass or backwards compatibility. Any information will appear on Xbox social media, and the usual news outlets.

But remember the vast majority of their delisted titles deal with intellectual property that they may not be able to reclaim the rights for.

Hi, yes Call of Duty games are wanted the most on the feedback site. But Microsoft cannot put these games on the backward compatibility until Activision gives them the go ahead to do it. The decision will always be made by the publishers of the games.
Gears of War is on it because Microsoft publish it. So if you want the games on the backward compatibility, then vote for it on the Xbox feedback website xbox.uservoice.com, and hopefully Activision
will allow MW2 & MW3 on there soon.

Hopefully that Call of Duty 3 will be available as part of the Backwards compatibility. I am pretty sure that someone from Microsoft are working with Activision to make their game available for the said Xbox One feature

Please hit like (solicitation)

Currently this title is not part of the backwards compatible catalog, you can go to xbox.uservoice.com and request this game become part of the backwards compatible catalog.

For a list of currently backwards compatible titles you can check here http://www.xbox.com/en-AU/xbox-one/backward-compatibility/available-games

Or here https://majornelson.com/blog/xbox-one-backward-compatibility/

Its Is the developers/publishers discretion to allow games to be backwards compatible, as of now there is no further releases planned for backward compatibility until scarlet is released with a supposed large back catalogue of games for backward compatibility.

It may well be worth contacting the developers directly with your wish for the game to be considered for this.