The re-elected incoming president Donald Trump campaigned on imposing high tariffs on China and all foreign entities—which economists have argued will have devastating consequences on domestic prices and trade relations. At Fortune’s Global Forum on Monday in New York City, Merit Janow, independent board chair at Mastercard and professor at Columbia University, weighed in on how these policies will impact U.S. businesses. Janow recalled bleak U.S.-China relations in the aftermath of the Tiananmen Square massacre in 1989, and how the countries’ partnership entered a dark period. But then came eras of great cross-trade, where both countries flourished. 

“There are deep structural tensions between the U.S. and China. I think this mindset that we have in the United States, that they are our principal geopolitical competitor, is going to stay with us,” she says. “So the experiences of business will vary by the sector very significantly.”

For the past 10 years, explained Janow, U.S.-China relations have grown steadily more challenging. Although President Biden tried to avoid conflict and introduce stability with China at the APEC summit in November this year, stress between the two global giants has persisted, she said. 

Janow pointed to the technology industry in particular. As China and the U.S. compete to be the biggest forces in the tech world, they have increased competitive restrictions in order to stay ahead. That geopolitical and business landscape is just one facet of how companies in both countries may start to diverge, as tariffs increase and competition heightens. 

“Are we moving into a more purposeful decoupling?” she asks. “There are a lot of questions about how this will evolve…We are not fully clear how much this tariff strategy will be deployed and [of] its consequences. [There is] a lot of uncertainty. But are there businesses that are still expanding in China? I think there are.”

Although Janow recognized that it’s too soon to know how Trump’s proposed tariff strategy will pan out, she described a lot of talk about how tariffs could worsen business relations between American and Chinese companies. She noted that after 10 years of effort, Mastercard was finally licensed to operate in China in 2023, and established a joint-venture in May of this year. But her business’ success story isn’t universal—many others may not have the same luck, depending on their industry and circumstances.

“The risks, the opportunities, the structure [are] very much different by the sector and history,” she says.