• Markets have been on a wild ride.
• Trump exempted smartphones, computers and other tech devices and components from his so-called reciprocal tariffs.
• Earnings season kicks off in earnest with big banks continuing to report along with Netflix.

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

1. Wild week

Stocks rose Friday, wrapping up one of the most volatile weeks ever on Wall Street. The S&P 500 added 1.81%, the Dow Jones Industrial Average climbed 619.05 points, or 1.56%, and the Nasdaq Composite rose 2.06% to end the week. Despite the rally last week, all three major averages are still down sharply since President Donald Trump announced his tariff policy at the beginning of the month. Since then, the S&P 500 has lost 5.4%, while the Nasdaq Composite and Dow Jones Industrial Average have fallen about 5% and 4.8%, respectively. Markets will be closed at the end of the week for the Good Friday holiday. Follow live market updates.

2. Tar-off and on

Trump exempted smartphones, computers and other tech devices and components from his so-called reciprocal tariffs late Friday evening, according to new guidance from U.S. Customs and Border Protection. The move came after the president hiked the total tariff rate on China to 145%, though the goods are still subject to 20% tariffs Trump earlier put on the country. The White House said the exemptions were to make sure companies have time to move production to the U.S. Even still, analysts say the idea of an American-made iPhone is impossible at worst and highly expensive at best. But confusion over the policy grew throughout the weekend, as Trump and his aides suggested the exemptions would be partially or completely reversed in coming weeks.

3. Earnings season

The lack of certainty in the markets is likely to result in some surprises as earnings season kicks off in earnest. Investors will be looking at companies' guidance more than ever. Goldman Sachs, which could prove to be a beneficiary of the recent market environment, kicked the week off Monday. Here are the companies reporting earnings to watch:

• Monday: Goldman Sachs Group, M&T Bank (before the bell)
• Tuesday: Citigroup, Bank of America, PNC Financial Services Group, Johnson & Johnson (before the bell); J.B. Hunt Transport Services, United Airlines (after the bell)
• Wednesday: U.S Bancorp, Citizens Financial Group, Prologis, Abbott Laboratories (before the bell); Kinder Morgan, CSX (after the bell)
• Thursday: Truist Financial, State Street, American Express, Fifth Third Bancorp, Regions Financial, UnitedHealth Group, Charles Schwab, Huntington Bancshares, D.R. Horton, Marsh & McLennan Cos. (before the bell); Netflix (after the bell) 

4. Pfizer pulls pill

Pfizer is ending the development of a one-daily weight-loss pill after a patient in a trial experienced a liver injury that was potentially caused by the drug. The patient's liver enzymes "recovered rapidly" after they stopped taking the pill, a Pfizer spokesperson said in a statement. The scrapping of the drug, an oral GLP-1 drug called danuglipron, is the latest setback for the pharmaceutical company as it tries to take on the lucrative GLP-1 market.

5. Auto focus

Trump's sectoral tariffs on autos remain in effect, and analysts are starting to detail what effect they might have on the industry. Goldman Sachs, for example, assumes new vehicle net prices in the U.S. will rise by roughly $2,000 to $4,000 over the next six to 12 months to better reflect tariff costs. Boston Consulting Group, meanwhile, estimates that tariffs will add $110 billion to $160 billion on an annual run rate basis in costs to the industry. "What we're seeing now is a structural shift, driven by policy, that's likely to be long-lasting," Felix Stellmaszek, Boston Consulting Group's global lead of automotive and mobility, told CNBC. 

— CNBC's Hakyung Kim, Sean Conlon, Erin Doherty, Lori Ann LaRocco, Sarah Min, Hugh Son, Annika Kim Constantino and Michael Wayland contributed to this report.