In Russia The triumph of Bolshevik Revolutionaries led to an exit from the World war I.
Step-by-step explanation:
The communists interference soon made them realise that the working class was being affected and was sacrificed for financial interests of the wealthy.
This led to the German freeing up the troops, they thought they have been benefited from Russia exit but it was not as good as a benefit.
The US entered the war because the Germans were not putting an end to the submarine warfare.