He competed in the 2014 Giro d’Italia. In December 2014 he was announced as part of the squad for the IAM Cycling team for 2015. He raced in the 2015 Tour de France, finishing in 19th place. Pantano was the winner of the fifteenth stage of the 2016 Tour de France, on a mountain stage across the Grand Colombier, from Bourg-en-Bresse to Culoz.

In July 2016 he replaced Nairo Quintana for selection in the individual road race at the Rio de Janeiro Olympics.

In 2016, he signed a two-year contract with Trek–Segafredo for the 2017 and 2018 seasons. Pantano agreed a two-year extension of his contract in 2018, through 2020.

In April 2019, Trek–Segafredo announced that Pantano had been ‘immediately suspended’ from the team after being notified that he had returned an adverse analytical finding (AAF) for EPO in a doping test carried out on 26 February. As a result of the AAF, he was provisionally suspended from the sport by the UCI, the sport’s international governing body. In June 2019, he announced his retirement from professional racing.

In May 2020, a UCI tribunal banned Pantano for four years for his 2019 positive test for the illegal performance-enhancing drug EPO. His ban was backdated to his initial provisional suspension, meaning he is unable to compete until April 2023.