The capitalization the parent poster used on Robotaxi may have been intentional to assist with interpretation. While it can be a generic term, I believe only Tesla uses it as a brand name: https://www.tesla.com/robotaxi
Robotaxi: Tesla's autonomously driven ride hailing service. Currently using Model Y's or whatever, maybe using Cybercabs once those actually exist, maybe eventually also leveraging Tesla vehicles owned by others (lmao no one who has though that through for more than a minute or two actually wants to risk their vehicle like that)
Cybercab: A Tesla vehicle explicitly built for the Robotaxi service, containing no driver controls whatsoever because they're expected to operate without any (local) human oversight