If I had to guess, this is probably fake, but it is worth mentioning. A listing for Call of Duty: Modern Warfare trilogy has appeared on Amazon.com in the UK as well as in Japan. However, there are a few oddities about the listing. Just check out the image below.
For starters, "Call Duty" is not a game and would be quite an oversight of a typo for a company like Activision. Secondly, why would Activision need an alternative account, Activision Classics, to sell the product, and not their main account? Thirdly, if you search Activision on Amazon, you will find that there are multiple accounts with the word "Activision" in it.
Activision, Activision Classics, Activision Blizzard and ACTIVISION are four of the top names that come back on the search. But why would a juggernaut company like Activision need that many accounts to sell their products? I find it highly unlikely that their sales department is just that incompetent at remembering a single password, so these are likely third party accounts.
On the other hand, is it possible that this is the reason we have yet to get any Call of Duty game on Backwards Compatibility for Xbox One? Maybe. It was recently leaked that a remastered version of Call of Duty: Modern Warfare would be coming with Call of Duty: Infinite Warfare.
By now it's a cliche, but pour as much salt on this as you can find. It's likely false.
Sources: [reddit, Amazon.co.uk]