It's hard to keep politics out of sports, especially at an international event like the Olympics. Some countries are represented under different names than most are used to.
Russia technically isn't represented in Tokyo, but the Russian Olympic Committee (ROC) is. The Refugee Olympic Team was created in 2015 ahead of the Games in Rio de Janeiro, Brazil as a reaction to a refugee crisis in Europe. And one island off the eastern coast of mainland China has been competing under a different name for nearly 40 years.
What many know as Taiwan has competed in the Olympics under the name Chinese Taipei (TPE) since the 1984 Games in Los Angeles. According to the International Olympic Committee, the island has been competing in Olympics since 1956, competing from 1956 to 1972 as "Republic of China," not to be confused with the People's Republic of China.
To understand the name, you have to go back even further than 1956. The Chinese Civil War ended in 1949, leaving both China (officially the People's Republic of China) and Taiwan (officially the Republic of China) both laying claim to the island. Both groups also claim to be the "true" Chinese state.
China does not consider Taiwan a country, and since 1979, neither has the United States. Having two groups competing in international competition, both claiming to be China creates a problem, logistically. About 10 months after the U.S. recognized the People's Republic of China as the official Chinese government, in October 1979, the IOC came to a compromise with the two groups, called the Nagoya Resolution, and required the Republic of China to compete under the name Chinese Taipei.
In 2018, some Taiwanese wanted IOC to change the national Olympic committee's name for the Tokyo Games, from Chinese Taipei to Taiwan, but Taiwanese voters voted against the change.
So, while diplomatic relations between the two groups and claims to the land remain contentious, the two are still able to compete alongside each other at the Olympic Games.