The Arnold Sky object offers a user-friendly approach to set up image-based lighting or a physical_sky.
See the skydome_light and physical_sky shader page for more information on their parameters.
You can choose between a sky (skydome_light with background enabled) and a physical_sky shader as the background via the Type combo box.
You can add light filters and set up light linking of the Arnold Sky object as by any other lights.
Light filter and light linking options
The Cinema 4D Sky object incorrectly flips the texture compared to Arnold. If you want a matching result, enable flip in the sky parameters.
If you already have an Arnold Sky object in the scene, then the background field of the Arnold Render Settings is not used.