TikTok is at a crossroads, as U.S. concerns about its Chinese ownership grow. Some officials have explored the idea of forcing a sale to a U.S. company. WSJ explains the challenges of making that happen. Illustration: Preston Jessee TikTok said it is launching a new product that will make it possible for publishers to sell ads alongside their posts, a shift for the video-sharing app, which historically has focused on independent creators. The product, Pulse Premiere, is the evolution of TikTok’s Pulse program, which allows an elite group of creators to collect half the revenue from video ads that appear...