why is campaign locked on call of duty: cold war

That's the date that Kennedy was assassinated, in case the theme behind the articles wasn't clear. If you take the unsubtly highlighted numbers from each article, in the order listed on the clipboard by the padlock you'll get 1, 1, 2, two, sixth, three (as written) or 112263 as a pure combination. He'll then ask you to make one more sacrifice and shoot you dead.

Once the recap has played out Adler will appear, to thank you for what you've done and the sacrifices you've made.

You'll then see some cut scenes outlining what happened, and recapping what you did with the two side missions. After a big battle you'll destroy the AA guns needed to let the US bombers destroy the site and prevent the detonation of the nukes around the world. Do that and you'll head there and take on Perseus' forces. Obviously for the good ending you want to pick Solovetsky. The nukes hidden all over Europe are going to detonate if you don't stop him, and you have two choices when Alder asks you where they can find him - you can tell the truth and say Solovetsky, or lie and say Duga. After the big twist - that you're really a Russian agent reprogrammed to believe they were a US operative in an attempt to extract the location of Perseus - you remember where he's hiding.

Why is campaign locked on call of duty: cold war