What happens if a player shows dissent to my decision?

The player is cautioned. IFAB's Law 6 guidance gives this example: the assistant referee indicates a throw-in for Team B, and a Team A player approaches the assistant referee and shows dissent. The referee cautions the Team A player, because public protest or disagreement (verbal and/or physical) with a decision is punishable by a yellow card regardless of whether it is directed at the referee, assistant referee or any other match official. Play restarts according to the previous decision (throw-in for Team B).

Match officials also operate under the referee's direction: in the event of undue interference or improper conduct by a match official, the referee will relieve them of their duties and report to the appropriate authorities.

Source: IFAB Laws of the Game 2026/27, Law 6 (The Other Match Officials): https://www.theifab.com/laws/latest/the-other-match-officials/