Here’s a quick guide to the Trump administration’s talks with a number of different countries about tariffs and trade, as markets prepare for another week of headlines and signs of potential agreements.

President Trump says he wants Xi Jinping, China’s leader, to call him to talk tariffs. Mr. Xi is ghosting Mr. Trump, and markets are plummeting.

China on Wednesday unexpectedly appointed a new trade negotiator key in any talks to resolve the escalating tariff war with the United States, replacing trade tsar Wang Shouwen with its envoy to the World Trade Organization.