• Tens of thousands of dock workers are back on the job as the port strike ended.
• New jobs data from the Labor Department on Friday is expected to be similar to August.
• U.S. crude oil prices rose about 5% on Thursday, the third consecutive session of gains.

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

1. Shaky October

Stocks fell again Thursday, with the Dow Jones Industrial Average dropping 184.93 points, or 0.44% for the day. The S&P 500, meanwhile, lost 0.17%, and nearly 4 out of every 5 S&P 500 members fell. The Nasdaq Composite was positive for the day, adding just 0.04%, thanks in part to a rally from Nvidia. Shares of the AI darling climbed more than 3%. October has gotten off to a shaky start as all three major averages are on pace to snap a three-week win streak. Follow live market updates.

2. Strike that

The port strike is over. A major union for U.S. dockworkers on the East Coast and Gulf Coast agreed to a tentative deal on wages with the United States Maritime Alliance late Thursday, sending tens of thousands of workers back to the job. The International Longshoremen's Association also agreed to extend its existing contract through Jan. 15 so the two sides could have time to finish negotiating a new contract. The strike, which started earlier this week, had snarled ports from Maine to Texas and threatened supplies of fruits, automobiles and other goods. Under the tentative agreement, ILU wages will increase 61.5% over six years, sources told CNBC's Lori Ann LaRocco, but key discussions about port automation are still under negotiation.

3. Jobs soared

New jobs data dropped from the Labor Department, and job creation turned out much better than the consensus forecast. Nonfarm payrolls jumped by about 254,000 in September and the unemployment rate dropped 0.1 percentage point to 4.1%. The Dow Jones consensus estimated a 150,000 increase with a steady 4.2% unemployment rate. The report likely locks in the Federal Reserve's decision to gradually reduce interest rates and eases concerns about the state of the labor market. U.S. Treasury yields jumped following the announcement, with the 10-year Treasury yield soaring more than 11 basis points to 3.967% and the 2-year Treasury yield climbing 15 basis points higher to 3.87%.

4. Oil in havoc

Since Iran launched a ballistic missile attack against Israel on Tuesday, speculation has grown that Israel could target the nation's oil industry in retaliation. Analysts told CNBC on Thursday that oil markets may be too complacent in the wake of Iran's attack, partly because geopolitical risks haven't resulted in oil supply losses since 2019. But Iran, one of OPEC's largest producers, makes up as much as 4% of the global oil supply. U.S. crude oil prices rose about 5% on Thursday, the third consecutive session of gains following Iran's attack. The rise on Thursday could have been in response to President Joe Biden's mixed comments on whether the U.S. would support an Israeli strike on Iranian oil facilities.

5. Wellness check

CVS is considering breaking the company up, but that could be risky. It's been dealing with high medical costs in its insurance unit and pharmacy reimbursement pressure. Now, the company has engaged advisors in a strategic review of its business and is weighing splitting up its retail pharmacy and insurance units, CNBC reported. But CVS risks losing the customers it peels off its vertically integrated business segments — not to mention revenue. The pharmacy chain has spent tens of billions of dollars on acquisitions to become a one-stop shop for consumers, but it's struggled recently, slashing its full-year 2024 earnings guidance for three consecutive quarters and seeing its stock fall more than 20% this year.

— CNBC's Lisa Kailai Han, Alex Harring, Kif Leswing, Lori Ann LaRocco, Jeff Cox, Sam Meredith, Spencer Kimball, Natasha Turak and Annika Kim Constantino contributed to this report.