Interestingly enough, a weapon from the original WWII-themed Call of Duty franchise will be brought into the modern-themed upcoming Call of Duty 4.
Thanks to http://www.charlieoscardelta.com user NXG_veXed for describing how he came about the information that the MP44 will be in CoD4, available to some militiamen as a surplus firearm. You'll have to sign up for membership on the site, then click HERE to view the topic.