Friendly target identification in radar
They use IFF (Identification Friend or Foe) for the Radar version of friendly target identification.
I'm afraid it's becoming a bit more complicated than that.
Being developed currently at the complete force organization level you have CJADC2 (Combined Joint All Domain Command and Control), the air force's contribution to which is the ABMS (Advanced Battle Management System)
The new tech for the Anti Aircraft part of this system is an evolving fully integrated air defense network which integrates all available sensors and effectors in the field and intelligently coordinates responses to threats (fire control decisions are made by a human).  It can be fed GPS positioning, signals from radars, radio signals, laser painted targets, whatever.  They've built the system with a flexible architecture so if they want to add a sensor type, they just need to write code to interface it.  For really complicated sensors like a camera, data interpretation can be done by a separate computer to generate the actual data fed to the system.  A single potential target could be observed at the same time by several radar systems, a friendly GPS signal and or transponder code from a BTID (Battlefield Target Identification Device) or GPS radio system, satellite camera or triangulation data from a sensor like a jet in flight or a robot dog.
Based on the article it appears they are designing it to be fairly intelligent, able to differentiate between actual targets and electronically spoofed targets, likely also disguised targets. It can reroute the sensor data &quot;tracks&quot; it finds valid between units (presumably so non-automated parts of units can see the correct data and respond) and provide alternatives in the case an effector fails.
As far as what it can control, pretty much any modernized automated weapon system (not necessarily automatic like a CIWS (Close In Weapons System), but capable of being computer controlled.  As another option, software can be written to interface with humans controlling non-automated systems by whatever form of messaging.  Aside from physical weaponry or deployment orders, it can advise for and control electronic warfare options, say, to hack a drone or missile in flight.
That said, part of the reason that parts of this system are being brought into existence is that friendly fire is still a problem.  In terms of things that have already been used, I found this article from 2007 about preventing friendly fire that seems to indicate that air to ground combat information was fed to pilots by control centers staffed by humans and a recent improvement made was to stream video from the aircraft so the person in the control center isn't working off of verbal description of the pilot of all things.  They mention that the BTID devices mentioned above are currently under evaluation and another option being evaluated was to use the GPS radio systems already integrated into some countries' machinery.  The precise state of military technology is often kept under wraps to some degree (a fair bit is obfuscated in these articles) but it's 2021 and 14 is a lot of years in technology time, so by now I would expect all the high end militaries to have fully integrated GPS at the vehicle level at the very least, likely GPS equipment at some squad level and possibly capability for individual soldiers.  Good old fashioned knowing where your stuff is can't really be completely replaced (true in the article if you read it), but as parts of it are enhanced and automated, friendly fire risk probably goes down.  With the right programming, based on all of it's sensor data and information about who or what should be where, the system would have a much better chance of identifying by inference a friendly target whose IFF transponder had failed.