Eighteen leaders of the world’s largest economies will gather in Argentina this week to watch two heavyweights duke it out in a diplomatic ring.

Heads of state and leaders from Europe, Asia and the Middle East will take their seats around the arena, and wait for US President Donald Trump and his Chinese counterpart Xi Jinping to signal where their trade war is heading. This year the G20, the annual meeting of the leaders of the world’s largest economic powers, will be a place where many will have to wait and see what the "G2’"W — the US and China — will decide.