The Russia Ban
For the 2018 games, the entire country of Russia was banned from competing in the Olympics. It had been discovered that not only had Russian athletes been doping, but they had done so as part of a state-sponsored scheme. In order to not punish Russian athletes who had not participated in the scheme, the Olympic committee said the athletes could still enter as individuals, but they had to wear a neutral uniform, and the Russian anthem would not be played. Russian athletes were evaluated on a case-by-case basis to determine eligibility.