Nuclear talks between Washington and Tehran missed a planned Friday start in Switzerland amid intensified fighting between Israel and Lebanon's Hezbollah. But with an Israel-Lebanon ceasefire in place by mid-Friday, the two sides could soon be back on track to kick off talks in the coming days, in the wake of US President Donald Trump and Iranian President Masoud Pezeshkian's separate signing of a 14-point memorandum of understanding (MOU) on Wednesday. Below, Energy Intelligence looks at the key issues at stake as the clock ticks on an extendable 60-day window for negotiations.