Just as long as people have ordered others to march into combat, so have cats marched into combat as well, but usually well behind the front lines so they can live in safety and comfort like the generals do.
In Egypt, Egyptians worshipped cats, so the Persians stormed the Egyptians by holding cats in front of them. That way if the Egyptians fired at them, they risked hurting or killing a cat.
During the Battle of Britain, cats would often hear German bombers approaching long before people would. As soon as the cats hid, the civilians would follow to avoid getting bombed by the Germans.