In August 2016, Trek–Segafredo announced that they had signed Guerreiro through to 2018.[5] He joined Team Katusha–Alpecin for the 2019 season, on a one-year contract.[6] In August 2019, he was named in the startlist for the 2019 Vuelta a España.[7]
In October 2020, he was named in the startlist for the 2020 Giro d'Italia.[8] He won the ninth stage and finished the race as the leader of the mountains classification, becoming the first Portuguese rider to win a Grand Tour classification.