Collaborate with: This is the most common and versatile option. It implies working *together* with someone else.
* Example: "We're collaborating with a local artist to create a mural."
Collaborate in: This implies working *together* within a larger context or project.
* Example: "We're collaborating in a research project to study climate change."
Here's how to decide:
* Focus on the entity: If you're working with another person or group, use "with."
* Focus on the context: If you're working within a larger project or situation, use "in."
Sometimes, both can work:
* Example: "We're collaborating with other teams in the development of this new product."
Let me know if you have a specific sentence in mind and I can help you choose the right preposition!