Iran and China have signed an economic and security cooperation deal that will see China invest $400 billion in Iran over the next quarter-century in exchange for regular deliveries of oil. The two nations will also set up an Iranian-Chinese bank that will help Iran circumvent U.S. sanctions that have largely cut it off from global banking systems. The U.S. sanctions were imposed after President Trump unilaterally pulled out of the landmark 2015 Iran nuclear deal.