Cab ML is both a standalone app and an AUv3 plugin that provides a neural network for impulse response generation. By moving tags in a window you can change the impulse response in an interactive way. Underlying a neural network will generate an impulse response based on the position of the tags. Instead of trying out all your impulse response files through a classic impulse response loader, you can now find the right sound interactively by moving the marks until you like what you hear. Furthermore Cab ML also provides a poweramp with many options and a microphone reverb generator.
The free version allows you to test Cab ML completely, but every minute the plugin will be silent for 3 seconds. To remove these limits there is a one time in-app purchase.
You need an audio interface to connect your instrument to your Mac. Known audio interface brands for guitar or bass are for instance Focusrite or iRig.
If you dont have an audio interface, you can use the AUv3 plugin in a DAW such as GarageBand or Logic Pro. Any (guitar/bass) sound you have recorded can be fed through the Cab ML audio unit.