It's still up in the air right now. There is a Space Force squadron that does one-way tracking and issues collision alerts, but no transponder standard or centralized traffic control. Companies, once alerted, coordinate individual collision avoidance maneuvers over email. It's ludicrous.

The govt still hasn't decided what agency will take the helm or what the system will look like. It hasn't been worth it to invest more until recently.

https://spacenews.com/from-space-traffic-awareness-to-space-...

Proposal for GPS-based sat transponders, analogous to radio-based aircraft transponders:

https://aerospace.org/sites/default/files/2018-05/GPS_Transp...