At first, the operation was largely successful. The Germans made it deep into Ukraine and Belorusse, took many prisoners, and caused heavy Russian losses. A Russian loss began to look like a real possibility. Soon, Moscow, Leningrad, and Stalingrad were under attack. However, The Germans were forced to retreat after losing the battle of Stalingrad, ultimately being forced out of Russia by the cold
It is arguable that the failure of operation Barbarossa resulted in the eventual defeat of the third reich.
As well, the operation opened the eastern front which would become one of the biggest areas of war throughout all of wwIi. The eastern front held some of the largest and most brutal battles of the war, along with miserable conditions and some of the largest death counts.