Almost any wireless link will be subject to man in the middle attacks by nature, in my view. If you can sniff the medium, you eventually can probably find a way

Almost any wireless link will be subject to man in the middle attacks by nature, in my view. If you can sniff the medium, you eventually can probably find a way to intercept it. Wired connections are more secure, or perceived to be so because the assumption is that sniffing the medium is more difficult, which is generally true because someone would have to physically make a connection (unauthorized) to your cable and the assumption is that it would be detected (perhaps). It's just a lot easier to sniff your channel over the air. 5G can be implemented on any piece of spectrum, sub-1Ghz, mid-Ghz or so called mm-wave. One thing about mm-wave that makes it "more cable like" is the highly directional nature. 5G that is being deployed on mm-wave bands (e.g. 28Ghz) have extremely small beam widths due to the use of Phased Array antennas. This makes it much more difficult to "sting-ray". or at least is more easily detected. Having said all this... everyone should always keep in mind that whatever wireless network you are on, GSM, CDMA, HSPA, LTE, Wifi, 5G whatever, you cannot count on the phy layer for protection.