What is the difference between pressure group and trade union?

A pressure group is an organization that seeks to influence public policy and decision-making without seeking to gain power through elections, often focusing on specific issues or causes. In contrast, a trade union is a collective organization of workers that aims to protect and advance their rights and interests, primarily in the workplace, through negotiations with employers and advocacy for labor-related policies. While both seek to influence change, pressure groups focus on broader societal issues, whereas trade unions are specifically concerned with labor rights and conditions.