Chairman - an executive body elected by the board of directors of the company, which is responsible for chairing the meetings of the board.
The chairman often sets the agenda and has significant influence on the council’s vote.
The CEO runs the company and is the person to whom the executives of the company report, but since the CEO is appointed by the board of directors, the chairman can influence who is elected CEO.
In some companies, the roles of CEO and chairman are combined, which can reduce transparency and accountability due to fewer checks and balances.