The four hot-button issues are Taiwan, democracy and human rights, China’s path and system, and the country’s rights to development.

“They must not be challenged,” Xi said, according to a statement published after the two leaders met on the sidelines of the 31st APEC Economic Leaders’ Meeting in Lima, Peru.

“These are the most important guardrails and safety nets for China-US relations,” Xi said.

https://www.yahoo.com/news/chinas-xi-sets-boundaries-trump-070934960.html

AND

Xi’s “Four Red Lines” For China Set To Clash With Trump’s ‘America First’ Trade Measures

https://www.zerohedge.com/geopolitical/xis-four-red-lines-china-set-clash-trumps-america-first-trade-measures