A collective bargaining agreement (CBA) is a written legal contract between an employer and a union representing the employees, usually governing pay and working conditions. In sports, it is therefore an agreement between the league and players, as represented by their players' association, or union. It is generally the league office's role to negotiate this contract on behalf of all its franchises.
The terms of a negotiation depend on the parties involved. Typically, team ownership will prioritize minimizing costs; athletes, on the other hand, negotiate for higher salaries and better working conditions. See the list below of the most common negotiating points for both players and owners when agreeing on a CBA. Notice that some items are of equal importance to both parties.