Social media company TikTok Inc. filed a lawsuit Monday seeking to overturn Montana’s first-in-the-nation ban on the video sharing app, arguing the law is an unconstitutional violation of free speech rights and is based on “unfounded speculation” that the Chinese government could access users’ data. The lawsuit by TikTok, owned by Chinese tech company ByteDance, follows one filed last week by five content creators. They made similar arguments including that the state of Montana has no authority to take action on matters of national security. Both lawsuits were filed in federal court in Missoula. Republican Gov. Greg Gianforte signed the...