The Science and Technology Agreement between China and the United States was the first ever official deal signed after the normalization of relations in 1979. But now, after 45 years, many hope the agreement will not be a casualty of cooling ties, after two partial six-month extensions have been in the pipeline since last year. But geopolitical tensions now once again complicate the decision, casting a pall over research cooperation between the world’s two science and tech hubs. So, what’s the outlook on China-US scientific cooperation? What could waning collaboration mean for the global science community?