If you slightly broaden your definition of 'cheating', you should consider Bobby Fischer's complaint of collusion during the 1962 World Chess Championship (See: https://en.wikipedia.org/wiki/World_Chess_Championship_1963).
In short, the World Chess Championship had qualifying rounds, where to advance, you needed to be one of the top candidates based on number of points accumulated during a round-robin stage. In such a system, a win is worth 1 point, and a draw is worth 1/2 points. Therefore if you are at the top of the leaderboard and are playing the 2nd place on the leaderboard, and you both tie, then you would both retain your respective #1 & #2 spots.
Fischer alleged that there was collusion amongst most of the the Soviet players, who agreed beforehand that they would draw against eachother in order to avoid a dreaded '0' points on a match. In particular, this agreement is alleged to have occurred when 'forced draws' between these Soviet players would have mathematically prevented Bobby Fischer from reaching the next stage in the championship. This collusion can be seen as sort of a 'nationalistic team spirit', when the WCC is supposed to be an individual competitor event.
Note also that 'agreed draws' were against the rules of the competition. In fact, no player was allowed to agree to a draw before the ~15th move, entirely to prevent such collusion. So instead, the Fischer alleged that the Soviet players colluded by playing well-known drawish lines, that lasted until after the 15th move, at which point they conveniently agreed to a draw. Fischer's allegation was predicated on the notion that players lower on the leaderboard would not have given their opponent a 'leg up' in the tournament by guaranteeing a draw - instead they should have been taking fighting chances for a win themselves.
There were 3 significant fallouts from these accusations:
(1) The ICC indirectly acknowledged Fischer's complaints by changing the format of the championship from Round-Robin to knockout elimination;
(2) The chess community was faced with direct proof of the problems caused by chess being increasingly 'drawish'. In this case, it was shown how convincingly the Soviets were able to play games that were entirely by the book, from first move to last, with no innovation. That conversation continues today (where the proportion of draws at top-level play continues to increase); and
(3) Bobby Fischer invented Fischer Random chess (AKA Chess960), which is a variant that includes randomly shuffling pieces for each player before play. Fischer argued that by randomizing the pieces, innovation would increase, and no similar collusion could occur, because there would be no such thing as a known tablebase of drawish games to collude with. [*Note that he did not invent Fischer Random until the 90's, so whether we can say the collusion strongly led to this or not is debatable].