Despite the entreaties of key European countries, US President Donald Trump broke the "nuclear agreement" with Iran, which was signed back when Barack Obama was. Germany, France and the United Kingdom failed to convince the American president to maintain the terms of the "deal" and now intend to act on this issue on their own.
Despite the fact that Trump threatened harsh sanctions to anyone who tries to circumvent American sanctions against Iran, European states are not going to curtail cooperation with the Islamic Republic. The European Union is not ready to lose billion contracts that were signed with Iran after the entry into force of the “nuclear agreement” in 2015.
For example, the French oil and gas company Total has managed to invest in Iranian projects very serious funds, and the aircraft manufacturer Airbus has orders from Tehran for more than 22 billion dollars. In the event that the EU supports the new sanctions, all these contracts will be terminated.
With all this, the only country that can somehow benefit from the US withdrawal from the agreement can be Russia.