[4][5] While he was vice president, the Hong Kong Federation of Students did not reach a consensus and therefore declined to attend the 26th anniversary of the 1989 Tiananmen Square protests for the first time.

[13] On 17 September, Cheung testified at the Congressional-Executive Commission on China (CECC) in Washington D.C., with activists Joshua Wong and Denise Ho.

"[13] In the months following Cheung's testimony, the Hong Kong Human Rights and Democracy Act was passed by the United States House of Representatives and the Senate.

"[18] In September 2019, Cheung met with a number of politicians across Australia, advocating for human rights clauses to be included in free trade agreements.

[19][20] In January 2020, he met with Taiwanese politician Chiu Chui-cheng to discuss forbidding Hong Kong police from entering the country.

[21] After the national security law was introduced in May, Cheung appealed to international governments to offer asylum and residency for the Hong Kong activists.

[26] He was one of the pro-democracy candidates who received letters from electoral officers on his positions on the national security law,[27] before the general election was postponed to 2021.

[28] On 15 September 2020, Cheung posted on social media that he had effectively left Hong Kong, though he did not say where he had fled to out of "security and strategic concerns".