Do some research. They’re completely different things. An MP3 is music, it tells the computer how to move the speakers. A MIDI file is the instructions to make music, it tells the computer what notes/instruments to play.
There is some sort of conversion software out there, but I doubt it’ll sound anything like the original. (It looks at the waveform and guesses what notes/instruments are playing. [I think.. I don’t actually know, just my guess.])