Cook sues Trump, S&P 500 hits a milestone, Nvidia's mystery clients and more in Morning Squawk

This is CNBC’s Morning Squawk newsletter. Subscribe here to receive future editions in your inbox.

Here are five key things investors need to know to start the trading day:

A federal judge set a hearing for 10 a.m. ET this morning after Federal Reserve Governor Lisa Cook sued President Donald Trump over his move to fire her. While the case will likely make its way to the Supreme Court, today’s hearing marks the latest twist in a dramatic standoff that has gripped economists and investors in recent weeks.

Here’s what to know:

The S&P 500