Complex sentence: Born and raised in Illinois, Davis began performing in 1940s New York with saxophonist Charlie Parker before recording the "Birth of the Cool" sessions for Capitol Records, which were instrumental to the development of cool jazz.
Split into simpler sentences: Born and raised in Illinois, Davis first performed in New York during the 1940s with saxophonist Charlie Parker. His "Birth of the Cool" sessions for Capitol Records were instrumental to the development of cool jazz.