One faculty may provide a one time guest lecture in a colleagues classroom because of a specific area of expertise connected to a particular course or theme.
Only one instructor is present at a time. Each of two (or several) instructors in turn teaches a half or corresponding fraction of a course. Faculty must coordinate their content to ensure that it is cohesive and not redundant, but they do not actually share teh teaching or grading.
The lead instructor of record for a course organizes the overall course and lines up a series of guest faculty experts for an extensive part of the course. Each guest faculty expert teaches one or two classes and/or acts as a support or resource instructor for targeted activities such as workships or integrating forums.
Two or more courses, each with its own instructor, are scheduled to meet at the same time and paired to the extent that they meet jointly with both instructors at intervals throughout the semester and/or share some assignments or projects.
Another way to implement this model is to package a set of two or three courses in different disciplines that are linked by common theme for offering in different time slots in a single semester to a single student cohort. In this example, the instructors of the connected courses team up to attract a common set of students, coordinate with each other to create sufficient coherence across the different courses, and provide some common integrating experiences to highlight the cross-disciplinary connections, similarities and differences. It is possible to create project assignments that would allow students to link what they are learning in the different courses.