WASHINGTON, May 29 : U.S. Democratic Senator Ed Markey on Friday formally asked TikTok's newly formed U.S. joint venture and cloud computing giant Oracle to explain how they are protecting the personal data of American users and preventing foreign entities from influencing which videos American users are shown on the app. The move comes four months after TikTok's Chinese owner ByteDance finalized a deal to transfer control of the app's U.S. user data and operations to the joint venture TikTok