The next crucial date to watch for clues on where the trade war is heading may be just around the corner — way before the end of the 90-day period that U.S. President Donald Trump and Chinese President Xi Jinping have agreed on to withhold further tariffs.

China marks the 40th anniversary of its economic reforms on Dec. 18, which is an occasion Beijing could use to emphasize its commitment to transform its economy, noted Scott Kennedy, deputy director of the Freeman Chair in China Studies and director of the Project on Chinese Business and Political Economy at the Center for Strategic and International Studies.

"If that day or week goes by with no major new announcements, then we know that for sure there's not a possibility that the Chinese want to use this as an opportunity to change the direction of their economy and industrial policies," Kennedy told CNBC's "Squawk Box" on Monday.

If that happens, the tariff fight between the U.S. and China will certainly re-escalate at the end of the 90-day period, he added.

Trump over the weekend agreed to not raise tariffs on $200 billion worth of Chinese imports from 10 percent to 25 percent in January as he had previous threatened, according to a White House statement. In exchange, the U.S. and China will work toward a deal within 90 days — a timeline that many experts have said is too short given the complicated issues surrounding the tariff fight.