Complex sentence: Chen made headlines for being one of the developers behind AlphaGo which defeated the world champion of board game Go Lee Sedol, Alpha go badly crushed Lee by winning four of the total number of five matches that they played against each other.
Split into simpler sentences: Chen made headlines for being one of the developers behind AlphaGo which defeated the world champion of board game Go Lee Sedol. AlphaGo badly crushed Lee during the competition by winning four of the total number of five matches that they played against each other.