In a letter to Director of the Department Cybersecurity and Infrastructure Security Agency, Department of Homeland Security, Christopher Krebs, the two senators Wyden and Rubio requested an investigation of possible risks stemming from VPN and data-saving apps based in unfriendly foreign nations. The growth of usage of mobile VPN and data-saving (proxying) apps of Russian and Chinese provider by government officials could harm U.S. National Security.
See the full letter: https://www.wyden.senate.gov/imo/media/doc/020719%20Wyden%20Rubio%20VPN%20Letter%20to%20DHS.pdf