Boxing is a sport practiced by two boxers in a ring, with a single referee.
Speaking generally*, there are 4 styles of boxing:
The Boxer: the boxer attempts to win the fight by striking his opponent while avoiding being struck. Boxers generally win many contests via decision, resulting in a low KO percentage. Many Boxers are adept counterpunchers. Boxers may depend on their boxing skills, or on athletic ability. Examples of Boxers who use skills are Billy Conn, Pernell Whittaker, and Willy Pep. Examples of Boxers who use athletic ability are Muhammed Ali and Roy Jones Jr. Boxers need good reflexes and excellent timing. Boxers have trouble with Swarmers.
The Swarmer: the Swarmer attempts to win a fight by overwhelming his opponent's defense with the volume of his punches. Good Swarmers shut down an opponent's offense by forcing them to spend all their energy covering up. Swarmers must have excellent stamina, and the best of them, Rocky Marciano, entered all of his fights in almost inhuman physical condition. Other notable Swarmers are Joe Frazier, Jake Lamotta, and Mike Tyson in his early years. Swarmers have trouble with Sluggers, and with Boxer-Punchers with sufficient power.
The Slugger: the Slugger depends on his punching power to win a fight. A Slugger will take punches to deliver punches, and thus one of the most important things a slugger needs is a good chin. The other is punching power. Mike Tyson in his later years has become a Slugger. Probably the best Slugger of all time was George Foreman. Sluggers have problems with Boxers, and Boxer-Punchers of sufficient skill.
The Boxer-Puncher: the most versatile style, the Boxer-Puncher uses his boxing skills to set up his power shots. Good Boxer-Punchers must be versatile, and able to think on their feet. They will have the skills to outbox the Slugger, the power to stop the Swarmer's attack, and will match the pure Boxer's skills with skills and punching power. Outstanding Boxer-Punchers include many legends: the heavyweight Joe Louis, the incomparable Sugar Ray Robinson, who many consider to be the best welterweight as well as in the top 2 or 3 middleweights of all time, welterweight legend Henry Armstrong, middleweights Carlos Monzon and Marvin Hagler, strawweight/junior flyweight Ricardo Lopez, light-heavyweight Archie Moore, and many more.
* - Most fighters are not a pure expression of a single style. Many of the best can (could), and do (did), switch styles from time to time as needed, and most fighters fit somewhere on a continuum, being somewhere between a boxer-puncher and a pure boxer, for example, or a swarmer that has elements of the pure boxer in his style.