China doesn't exactly limit its activities to people within its borders. There are reports of Uighurs speaking up who get harassed after fleeing the country and speaking up: https://www.bbc.com/news/world-asia-china-56563449

Five men were charged with stalking and harassing Chinese dissidents in the US, including by seeking to derail the election bid of a congressional candidate: https://www.asiafinancial.com/five-charged-with-harassment-o...