I would venture to guess that in many states, if you graduate from a certified school, you can get a state issued license.
I was listening to the Vince podcast where he discussed this, and it sounds incredibly corrupt.
That appears to be the case: https://en.wikipedia.org/wiki/Commercial_driver‘s_license
“Employers, training facilities, states, governmental departments, and private institutions may be permitted to administer knowledge and driving test for the state. The test must be the same as those given by the state issuing the CDL, and the instructors must meet the same professional certification as state instructors.”
....many years ago (MANY...!) having sat in the sun too long without a hat, I had the desire to get my CDL and DRIVE THE BIG RIGS..! I enrolled in a local community college’s CDL program...and the classroom work was pretty heavy..! I cannot fathom how anyone who cannot understand English could have gotten a CDL...!! Subjects included air brakes, HAZMAT cargoes, road saftey, legal hours-of-service, and many others....these CDL holders who got their licenses fraudulently should all be jailed...!!