Kai Chen, a Canadian AI researcher who worked on OpenAI’s GPT-4.5, has been denied a U.S. green card after living and contributing in the country for 12 years, according to OpenAI research scientist Noam Brown. Brown, posting on X, said that Chen learned of the denial on Friday and must soon leave the United States.
“It’s deeply concerning that one of the best AI researchers I’ve worked with was denied a U.S. green card,” Brown wrote. “We’re risking America’s AI leadership when we turn away talent like this.” Another OpenAI employee, Dylan Hunn, emphasized that Chen was “crucial” to the development of GPT-4.5.
It's deeply concerning that one of the best AI researchers I've worked with, @kaicathyc, was denied a U.S. green card today. A Canadian who's lived and contributed here for 12 years now has to leave. We’re risking America’s AI leadership when we turn away talent like this.
— Noam Brown (@polynoamial) April 25, 2025
While the green card denial won’t cost Chen her job, she will now work remotely from an Airbnb in Vancouver until her situation is resolved, Brown noted. OpenAI later clarified that Chen’s green card application was filed before she joined the company, and that some paperwork issues may have affected the case. The company is reportedly working closely with her on the matter.
This case highlights the broader difficulties facing foreign talent in the U.S. under the Trump administration. Over the past few months, more than 1,700 international students and researchers have seen their visa statuses challenged. While some students faced accusations of supporting militant groups, others were targeted for minor infractions like speeding tickets.
Although the administration recently reversed some visa cancellations, immigration uncertainty remains high. New regulations are being drafted that could introduce stricter visa review processes.
AI companies like OpenAI heavily rely on international talent. In 2024 alone, OpenAI filed over 80 applications for H-1B visas. The tech industry at large depends on foreign researchers; a study by Georgetown’s Center for Security and Emerging Technology found that 66% of the top U.S.-based AI startups had at least one immigrant founder. Another analysis revealed that 70% of full-time AI graduate students are international.
U.S. immigration policies, reduced grant funding, and growing hostility toward scientific fields have left many researchers contemplating moving abroad. In a Nature poll, 75% of 1,600 surveyed scientists said they were considering leaving the U.S. for jobs overseas.
The loss of talents like Kai Chen could have long-term implications for America’s position in the global AI race.
