A new CAS hearing is due to take place following the Swiss Federal Tribunal's decision to remove the previous President of the panel Franco Frattini on December 22.

A series of tweets from Frattini about China's dog-meat trade came to light several weeks after the CAS ruling, including one where Frattini uses a racial slur.

Yang's appeal against an eight-year doping ban was upheld, meaning the case would need to be heard again.

Hans Nater of Switzerland will act as President on the panel, and will be joined by Jan Paulsson of France and Bernard Hanotiau of Belgium.

Due to the COVID-19 pandemic, the hearing is set to be held online via video conference.

This will be the resumption of the case brought by WADA against Sun and the International Swimming Federation (FINA), in relation to a decision issued by the FINA Doping Panel on January 3 2019.

In this FINA panel decision, Sun was found not to have committed an anti-doping rule violation following an out-of-competition doping control.

In February 2020, Sun was banned for eight years after a member of his entourage smashed a blood vial with a hammer during an attempted drugs test in September 2018.

WADA appealed to CAS about FINA's decision, leading to the swimmer being handed an eight-year ban by the CAS panel that was led by Frattini.

The decision was made following a 10-hour public hearing in November 2019.

This looked to have ended Sun's chances of competing at the Tokyo 2020 Olympics and effectively ended his career.

Sun is an 11-time world champion and a three-time Olympic gold medallist. 

He has denied any wrongdoing, claiming the officials who arrived to test him at his home on the night in question did not have the correct credentials.

Sun's first CAS hearing was plagued with translation issues, leading to an interpreter appointed by his team being replaced by a WADA staff member.

His behaviour during the hearing was also criticised by some observers.

Usually behind closed doors, Sun's first CAS hearing was the first public hearing this millennium. 

Sun is regarded as a controversial figure in the swimming community and previously served a three month drugs ban in 2014 after testing positive for trimetazidine, a stimulant that had received banned status four months earlier.

At the 2019 FINA World Championships, Australia's Mack Horton and Britain's Duncan Scott both refused to share the podium with Sun in light of the blood vial incident.