Popular yet increasingly politically sensitive social media app TikTok and its parent company ByteDance are once again drawing the attention of U.S. lawmakers, owing to recent changes to the app's privacy policy, as well as an investment from the Chinese government.

A subtle but troubling change to TikTok's privacy policy caught the ire of Senators Amy Klobuchar and John Thune, D-Minnesota and R-South Dakota, respectively. The changes would allow the app to automatically harvest biometric data from users, including voice and face "prints." In a letter sent to ByteDance CEO Shou Zi Chew, the senators asked for clarification on what the company meant by "voiceprints" and "faceprints" and which parties the data is being shared with.

"The coronavirus pandemic led to an increase in online activity, which has magnified the need to protect consumers' privacy," the letter said. "This is especially true for children and teenagers, who comprise more than 32% of TikTok's active users and have relied on online applications such as TikTok for entertainment and for interaction with their friends and loved ones."

Compounding with the recent letter is a renewed call to ban TikTok from the United States by GOP Senator Marco Rubio of Florida. Senator Rubio called on President Joe Biden (who reversed former President Donald Trump's attempted ban of the app) to take action against the social media app, citing a recent investment in a China-based ByteDance subsidiary by a state-owned firm. Along with the investment, the Chinese government has placed a member on the company's board of directors.

With Biden seeming to prefer an alternative to an outright ban, but the forced sale of TikTok to an American firm fizzling out last year, the most likely solution to the concerns that consumers, advocates, and lawmakers have over the app will come with the conclusion of a currently ongoing security review by the Committee on Foreign Investment in the United States.