Just got done watching Fury, and it was a fantastic movie. There was a scene where a SS battalion on the front marched in step and sang while moving, and it struck me as odd- something that, as a Marine, I know you would never see on any modern army.
I don't really know how accurate Fury is, but it does put on pretenses of being 'authentic', so I'm wondering if this is something that would have been done.
Didn't saw the movie yet but singing while marching was pretty common in the Wehrmacht. Many divisions had their own special songs. Marching long distances was more common in the Wehrmacht than other armies since the ratio of motorized support to infantry was far lower than in other armies. Many of these so called "Marschlieder" are now banned.
Iam no expert for the Red Army but i think singing there was also common.
Btw singing in modern army happens.
Edit: For clarification if you mean with "on the front" directly in combat, then highly unlikely...