There were concerns that Huawei was embedding nefarious capabilities in their communication capabilities to control the grid and potentially spy on users of the cell phones they manufacture.
Likewise, the concern with TikTok is spying ... why do you suppose the Biden campaign ordered its staff to delete TikTok for security reasons? Why do you suppose the DNC has warned its members about using TikTok? The Army? The Navy?
https://www.cnn.com/2020/07/28/politics/biden-campaign-tiktok/index.html
https://edition.cnn.com/2020/07/10/politics/dnc-warning-tiktok/index.html
https://www.washingtonpost.com/technology/2019/12/31/us-army-bans-tiktok-military-devices-signaling-growing-concern-about-apps-chinese-roots/
https://www.reuters.com/article/us-usa-tiktok-navy-idUSKBN1YO2HU