Broken codes let the allies know where major forces were being moved. So the US fleet could choose where to intercept the Japanese Navy for the Battle of Midway. Radar and sonar then provided realtime tracking of the Japanese forces during the battle.
This is a summary of information from a Foreign Policy article by Thomas E. Ricks.
Quantum entanglement, quantum superposition, and quantum tunneling can be applied in new forms of computation, sensing, and cryptography.
Even many non-technical people know that breakthroughs in quantum computing can be used to break current encryption and security. We are rapidly approaching the scale of quantum computing which will make current security more vulnerable. This would provide the same kinds of military advantages as the breaking of the German and Japanese codes in WW2.