There's a lot of pieces to this question and it sounds like you've already split some of them off to other sites which is good. It's still a little unclear what you're trying to do with the radio itself:
Send the audio buffer from the transmitter to the microcontroller
In the United States, the Citizens Band Radio Service refers to just one specific set of channels and those are only allowed to be used for voice transmissions (among other restrictions). There are similar restrictions on the Family Radio Service.
That is, neither CB ("trucker" radios) nor FRS ("hiking" walkie-talkies) are allowed for much beyond people talking live with nearby people, and only using unmodified store-bought equipment.
There are only a few casual options where data transmission is allowed:
- other more specialized Part 95 devices like remote controllers or Multi-Use Radio Service equipment may transmit data but end-users might not be allowed to modify it much
- the Amateur Radio Service has relatively few technical restrictions, but may only be used for certain purposes — and requires a "ham" license
- Low power Part 15 stuff (e.g. WiFi, Bluetooth, tiny FM transmitters for your car)
But from some of your other comments, it sounds like you might only be interested in gathering received audio rather than transmitting it yourself? (In radio terms we distinguish a "transmitter" sending signals from a "receiver" listening for them. A "transceiver" can do both, though not necessarily at the same time.)
If you are trying to do something like "scanner monitoring" that's a bit different situation. There may already be lots of options available for that, if you gather the right pieces:
For example the Uniden BCD536HP scanner is a receiver only but can be configured to listen to the CB (and many many other) bands and has Wi-Fi feature already.
Or with the right adapters to reduce the speaker output level of the CB receiver safely as a mic input to an old smartphone, there is likely software available to "stream" that audio to an Internet protocol server.
Similar if you need to use a microcontroller instead: if you already have a solution for the "capturing and/or generating audio" piece and the "connecting to WiFi" piece and the "transmitting audio data to a server" piece, then perhaps you might open a new question about any remaining radio-specific pieces (e.g. dealing with the audio input/output of a transceiver) here on this StackExchange site.