[7] In 2015, Buchmann denied the strong sprinters their chance at the German National Road Race Championships when he attacked from a leading group to take the title.

[1] After a quieter 2016 season, he finished tenth at the 2017 Tour de Romandie, losing a podium position only during the race's final stage time trial.

[6] Buchmann then finished seventh overall and first in the young riders' classification at the Critérium du Dauphiné, one of the major preparation races for the Tour de France.

During the last stage, he finished ahead of strong general classification riders such as Chris Froome, Alejandro Valverde and Alberto Contador at Plateau de Solaison.

[9] At the German National Road Race Championships the week after, Buchmann set up the victory for his teammate Marcus Burghardt, finishing in second place.

[10] His form faded slightly at the Tour de France, where he was set to work for team leader Rafał Majka, who withdrew early;[11] he eventually finished in 15th place overall.

At the Critérium du Dauphiné in June, Buchmann finished sixth in the general classification, repeating his strong performance from the previous year.

[15] After falling back during the subsequent mountain stages,[16] Buchmann eventually finished the Vuelta in 12th place overall, his best result in a Grand Tour up to that point.

For 2021, Buchmann initially chose to forgo the Tour de France, due to its route not suiting his strengths, containing too many time trials and too little mountain-top finishes.