In 1914 during the war German, British and some French soldiers agreed a ceasefire for Christmas and a couple of days after that.
The opposing sides didn’t want to fight each other because they didn’t want bloodshed on that day. Some soldiers exchanged wine and cognac and played games of football with each other. The truce was unofficial. If found out soldiers could be shot for their actions. The commanders did find out and some soldiers were actually supposed to be shot but the press was too persistent and the execution orders were cancelled.
The sides were sent to different fronts after the leaders realized they didn’t need soldiers who would not fight against each other. The soldiers did the right thing. They wanted to have a bit of relaxation.