U.S. and Iranian negotiators have reached an agreement on a 60-day memorandum of understanding to extend the ceasefire and launch negotiations on Iran's nuclear program, but President Trump has yet to give his final approval, two U.S. officials and a regional source involved in the mediation efforts tell Axios. Why it matters: The signing of the MOU would be the most significant diplomatic breakthrough since the war started, but a final agreement that tackles Trump's nuclear demands would still