1. Feature Driven vs. Test-Driven Development: One key difference between Cucumber and xUnit is the focus of their development processes. Cucumber follows a feature-driven approach, where tests are written to validate the behavior of a feature from an end user's perspective. On the other hand, xUnit follows a test-driven development approach, where tests are written to validate the behavior of individual code units or components.

2. Domain Specific Language vs. General-purpose Framework: Cucumber employs a domain-specific language (DSL) called Gherkin for writing its tests. Gherkin uses natural language constructs like Given, When, and Then to define test scenarios in a structured manner. In contrast, xUnit frameworks are typically general-purpose testing frameworks that do not use a specific DSL, allowing developers to write tests using the programming language of their choice.

3. BDD vs. TDD: Cucumber is primarily associated with Behavior-Driven Development (BDD), which emphasizes collaboration between technical and non-technical stakeholders to define and validate software requirements. On the other hand, xUnit frameworks are commonly used for Test-Driven Development (TDD), where tests are written before implementing the corresponding code to drive the development process.

4. Human-readable vs. Technical-focused tests: Another significant difference is the nature of tests written in Cucumber and xUnit. Cucumber tests are typically more human-readable and descriptive, making them accessible to non-technical stakeholders such as business analysts. In contrast, xUnit tests are often more technical and focused on the implementation details of the code being tested, catering more to developers and testers familiar with the technology stack.

5. Collaboration vs. Isolation: Cucumber promotes collaboration among team members by encouraging the use of plain language specifications that can be understood by both technical and non-technical stakeholders. In contrast, xUnit tests often focus on isolating and testing individual code units in a controlled environment, emphasizing the technical aspects of testing over collaboration.

6. Tool Ecosystem: Cucumber typically comes with a rich ecosystem of tools and integrations that support its BDD approach, including plugins for integrating with various testing frameworks and tools like Jira for managing feature files. xUnit frameworks, on the other hand, may have a more focused toolset geared towards traditional unit testing and code coverage analysis.

In Summary, Cucumber and xUnit differ in their development approaches, testing methodologies, focus on collaboration vs. technical aspects, and the nature of tests they produce.