Is Tor browser illegal?

I'm curious, when it comes to using the Tor browser, is it considered illegal? I've heard mixed opinions on this topic, and I'd like to get a clearer understanding. After all, Tor is often associated with anonymity and privacy, which can sometimes raise concerns in the context of legal and ethical frameworks. So, is the mere act of downloading and using the Tor browser against any laws, or is it the activities that one engages in while using it that could potentially be illegal?