USB-to-aux cables exist, but in most cases, they don't work as a conduit for digital music to your car radio.
Belkin 3.5 mm Audio + USB-C Charge Adapter
【PLAY MUSIC IN CAR OR SPEAKER】: This product allows your U disk to play music in the car audio system or 3.5mm speaker. (This product requires an
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About Product: Nowadays, more and more car models have canceled the original 3.5mm AUX-IN function, which has caused the sound of many external A/V devices like a digital TV tuner, screen mirroring adapter, HD multimedia player, etc. could not be directly transmitted to the factory car audio system. This AUX-USB module could stream external audio to OEM stereo via a factory USB port with lossless. It's very simple to use, no wiring required, plug and play.
Specific AUX-USB Audio Adapter for Select Car Models Without Original 3.5mm Aux Input Jack