https://apnews.com/ab0a7bde413998f836fc04836321e07a > HONG KONG (AP) — TikTok CEO Kevin Mayer resigned Thursday amid U.S. pressure for its Chinese owner to sell the popular video app, which the White House says is a security risk. > In a letter to employees, Mayer said that his decision to leave comes after the “political environment has sharply changed.”