1. Storage and Organization: One key difference between OneNote and Trello is that OneNote primarily focuses on note-taking, allowing users to store and organize information in a digital notebook format. On the other hand, Trello is more geared towards project management, enabling users to create boards, lists, and cards to help organize tasks and workflows efficiently.

2. Collaboration Features: While both OneNote and Trello offer collaboration features, Trello excels in real-time collaboration with its ability for team members to work simultaneously on boards and cards. In contrast, OneNote supports collaboration through sharing notebooks, but lacks the same level of real-time interaction that Trello provides.

3. Task Management: Trello is known for its robust task management capabilities, allowing users to assign tasks, set deadlines, and track progress easily within the platform. OneNote, on the other hand, offers basic task management features but may not be as sophisticated as Trello in terms of tracking and managing tasks efficiently.

4. Integration with Other Apps: Trello is known for its seamless integration with various third-party apps and services, making it easy for users to connect Trello with other tools they use regularly. On the contrary, OneNote may have limited integration options, which could impact its versatility and compatibility with other apps.

In Summary, OneNote focuses on note-taking and organization, while Trello is more focused on project management, offering robust collaboration features, task management capabilities, and better integration with third-party apps.