A memo that circulated among U.S. policymakers cited intelligence that Alice Huang, a Chinese executive who developed a relationship with Nvidia’s leader, was an asset of Beijing’s Ministry of State Security.

© Manuel Orbegozo for The New York Times

A summit could bolster Xi Jinping’s stature. But talks about Ukraine’s future and limits on nuclear weapons pose uncomfortable choices for China.

© Haiyun Jiang/The New York Times

China and the U.S. need mutually assured collaboration to quash the threat of A.I.-empowered bad actors, even while their economic differences sharpen.