I think we can all guess what the campaign beats will be here, as most COD campaigns are explosive shooter fests, which is why levels like "All Ghillied Up" are so memorable. But maybe for a story and setting which are a little more sombre they could, even for one level, just have a little adventure during a soldier's downtime, maybe asking around for a missing important item, trying to trade something for cigarettes, losing a boot during the last fight then hunting for a new one... pretty much anything except shooting. I think back on my favorite WW2 based media Band of Brothers, and it's all the many parts in between gun fights where the characters grow on you.