Trademark:

A trademark is a distinctive sign that identifies a certain product or service as being produced or provided by a specific individual or enterprise. (Official website of the World Intellectual Property Organization)

Visible signs (including text, graphics, letters, numbers, three-dimensional logo and color combinations, and combinations of the above elements). (According to the Trademark Law of the People's Republic of China and the People's Republic of China)

Logo:

As the name suggests, it usually refers to a company or enterprise's unique image logo that distinguishes it from other companies.

Trademarks are usually for products, and logos are usually for businesses. Trademarks need to be registered by the industrial and commercial department, but trademarks do not.