Markus came in second at the age of 19 at the Dutch National Road Cycling Championships. In 2019 she was European and world champion in the mixed team relay. Last year Markus won the second stage of the Ladies Tour of Norway; it was her first win in a World Tour race. Since June 2022, Markus has been wearing the Dutch jersey for a year, because she became champion on the road. In 2023, she became Dutch TT champion. Markus has the ambition to qualify for the time trial part at the Olympic Games in Paris (2024).