Complex sentence: The Chiefs' concessionaire is Sportservice, based out of Buffalo, New York Among other stadiums the company services are Busch Stadium in St. Louis and Comiskey Park and Soldier Field in Chicago.
Split into simpler sentences: The Chiefs' concessionaire is Sportservice, out of Buffalo, New York. Other stadiums the company services include Busch Stadium in St. Louis and Comiskey Park and Soldier Field in Chicago.