U.S. President Donald Trump has appointed Vice President JD Vance to oversee the negotiations on a deal to save the operations of TikTok in the U.S.TikTok, owned by ByteDance Ltd., has been in a legal limbo since being banned in the U.S. on Jan. 19.Potential buyers for TikTok's U.S. operations include Oracle Corp., Microsoft Corp., and Amazon.com Inc.TikTok and its backers are exploring the option of a joint venture with U.S. investors to address data security concerns.