USB Microphones have become a popular recording method for everyone from podcasters, to streamers, to beatmakers on the go for sampling. While we would always recommend using cables through an interface(either through the MPC's own or an external one, please see Akai Pro MPC | Can I connect a Microphone into a Standalone MPC? for information on this setup), in this guide we'll walk through the do's, don'ts and considerations for a USB Microphone setup.
When a USB microphone is connected up to the MPC, it is generically treated as a USB Audio Interface. Luckily, most USB Mics are usually class compliant anyways, so they should work out of the box. Please check with the manufacturer of the microphone for more information. Because USB Mics are treated like interfaces, when the MPC attempts to use it, it's going to cede all Input/Output audio through it, disabling it's own capabilities. This would need to be setup in the MPC's preferences for the Audio tab. What that means is that the Mic itself needs to have it's own audio output(usually in the form of a monitoring/headphone output on the device itself) or else it will not be able to have sound output and effectively be useless.
For more information about setting up an MPC with a USB audio interface, please see Akai Pro MPC | Can I connect a Microphone into a Standalone MPC? which will walk you through the process of setting the MPC's Audio Input/Output to an external device.
Afterwards, you would simply connect your own headphones to the headphone port on the microphone and be able to use the mic with the MPC.