Complex sentence: In May 2013, Major League Soccer announced that their 20th franchise would be a different New York--based team, New York City FC, a new team co-owned by English Premier League team Manchester City and Major League Baseball team the New York Yankees.
Split into simpler sentences: In May 2013, Major League Soccer announced that their 20th franchise would be a different New York--based team, New York City FC. Unlike the Cosmos, NYCFC was a new team founded by English Premier League team Manchester City and Major League Baseball team the New York Yankees.