There is more than one artist using the name R.I.O.
1) R.I.O. is a german danceproject from the producers Manuel Reuter (Manian) and Yann Pfeiffer (Yanou). The vocals are from Neal Antone aka Tony T, who was in the nineties the rapper of Beat System. The project started in 2007. Read more about R.I.O. on Wikipedia.
2) R.I.O. is a british Grime artist. Born in Manchester, he spent some of his teenage years living on the Carribean island of St. Vincent, and even represented the Island in a World Cup qualifier against Cuba. He moved back to England to pursue his football career, and had a trial at Manchester City. He failed to secure a deal with the club and decided to pursue his music career in stead.
3) R.I.O. is a duo that lives and works in Buenos Aires, Argentina. Their music is in the line between free improvisation, electronica, noise, free jazz and ambient.
Their members are Sergio Merce (Tenor sax, WX7, Electronics) and Lucas Totino Tedesco (Lap steel guitar, electronics), both from Buenos Aires.