Cinemachine supports orthographic cameras. When you set the Unity camera's projection to Orthographic, Cinemachine adjusts to accommodate it. In Virtual Camera properties for Lens, FOV is replaced by Orthographic Size. Note that settings related to FOV and certain FOV-oriented behaviors such as Follow Zoom have no effect if the camera is orthographic.
In orthographic environments, it doesn’t usually make sense to rotate the camera. Accordingly, Cinemachine offers the Framing Transposer to handle framing and composition without rotating the camera.