The Apertura 2015 saw Sosa become the star man for Pumas and became only the 5th pumas player to score 10 or more goals in the short tournament format, scoring 10 goals. He also added 7 assists during the regular season. On December 9, 2015 Club Universidad Nacional tied Sosa down for another three years to the club.
During Apertura 2015, Sosa became the central figure for Pumas, setting a record as the fifth player to reach 10 or more goals in the condensed tournament format. He also added 7 assists during the regular campaign. In December 2015, Club Universidad Nacional agreed to keep Sosa with the club for an additional three years.