If you're talking about passive signal tracking, I can talk about the technical generalities of how it's done.
When you go to a medium to large business, they have WiFI access points from companies like Cisco Meraki, Unifi, Aruba, Ruckus, Juniper, and so on. The common thing between all enterprise access points is that they're centrally managed. There's a server somewhere, usually at the company that's managing their networking (so not even owned by the company that provides the WiFI but sort of a "cloud" SaaS thing) that all the access points connect to and not only pull the configuration and software updates from, but send statistics and data back to. Stuff like connected client MACs and signal strengths and data flows, but also scans of the local radio spectrum to identify foreign access points that are on the same frequency and to alert the sysadmin that there's potential for interference. So the technology has been there for at least 2 decades to track people based on their client MACs. Usually you'd have to connect to the AP to be logged, but just turning on your own hotspot will get you logged too.
The database with all this data is at the companies that manage these network devices, and they'll definitely get requests from law enforcement to track users. The question is how large the scope of data they hand over is, and whether they do any filtering at all or just hand over the entire database, that the cops then upload to the feds central servers, where they further process it and feed it into larger databases that combine tracking data from multiple sources, like from cell phone tracking and now from these new AI-powered cameras.
Regarding passive signal tracking via Bluetooth and other frequency emissions, like NFC and ISM-band stuff like TPMS sensors. Yes, it's definitely possible. Who knows if these closed-source proprietary access points, that on paper should just do WiFI stuff, also listen in to Bluetooth. WiFI and Bluetooth operate on the same 2.4GHz frequencies, so the hardware to receive Bluetooth emissions is already there, it's just a software thing to decode and upload it.
NFC and ISM band stuff is a bit harder, as it's usually in frequency bands that are far from those used by WiFI, so the antennas designed for 2.4GHz can't receive it. But if the hardware is designed with the right antennas and radios to receive it, and they install this hardware on the streets or in businesses, like they're doing with these new cameras (they could even integrate the passive radio receivers and camera together into an all-in-one tracking device) it's definitely possible to track people with passive emissions.
You can significantly lower your risk by not using Bluetooth stuff,, turning off WiFI when you're not using it, turning off the cell modem (although it's only possible if you use a phone with a hardware killswitch like a Pinephone or Librem), not driving a car made in the last 10-15 years (before they started putting telematics and TPMS into every car).
The largest risk of tracking that everyone has on them is their cell phone. Nobody turns their modem off, even if they could. (you can't even turn it off on all phones that don't have a hardware kill switch, that airplane mode setting in the OS is just a suggestion, the modem is still turned on all the time). You can put it in an antistatic or EMI shielding bag that acts as a faraday cage for RF.