Many people think that, in the time of the USSR, Russian chess players conspired to make sure a Soviet player won tournaments.

For example, they would try harder to beat strong non-Soviet players than to beat strong Soviet players, would throw away games to give a Soviet player more points, would offer a draw very soon to give a Soviet player time to rest/prepare for theirnext matig, etc.

There’s also https://en.wikipedia.org/wiki/World_Chess_Championship_1948#...

World Chess Championship 1972 was widely viewed as a proxy for the Cold War

Fischer - Spassky 1972