As far as I remember, Mike Tyson once was present at a Bob Sapp fight. Afterwards Sapp wanted Tyson to come into the ring, what Tyson did. Sapp tried to attack Mike, but Mike stayed cool and was laughing at him. Later on Tyson said Sapp should sign the contract.
Tyson signed a contract with a K1 organization, but it is limited to boxing matches only - I do not think Tyson will ever try kickboxing, his sport was and still is boxing.
We were having a discussion about that
here as well.