I assume by "camera" you mean data which will be used to set the view matrix for rendering. Is that correct?

If so, can you describe in a bit more detail how you want the camera to behave? I.e., what do you mean by "orbit?" Orbit the world origin? Orbit an object?

Commonly, one defines a camera position, up and look-at vectors. The view matrix is then constructed with (something equivalent to) XMMatrixLookAtLH(...).

One approach would be to calculate the camera's position from the object's position, given a changing value.

E.g., assuming Y is the up-axis, calculate a vector based on time - vector.x = sin(time); vector.z = cos(time); let vector.y remain the same (however "high" above the object you want it to be.)

The camera's position = object position + some_scale_distance*vector. Keep the camera's up vector (0,1,0) and look-at vector (the object's position) the same. Create the view matrix as mentioned above.

You can use your current view matrix functions, and just modify their input to an appropriate new model. For example, if you want the camera view to rotate around an object, your look at point would be the center of the object. Then the location for your 'look from' point can be calculated with spherical coordinates each frame. This lets you easily increment the values of the spherical coordinates, which then get translated into a position.

Like Buckeye said, there are lots of ways to do it. If you provide a little more detail about what you are currently using for your view matrix generation, we can probably give you a more specific answer.