eARC, also known as Enhanced Audio Return Channel, is an updated version of the current HDMI ARC, and is a feature of the new HDMI 2.1 standard. It functions just like the former ARC feature but will also support uncompressed advanced audio formats (Dolby Atmos, DTS:X, DTS-HD Master Audio, etc) for a better audio experience. In addition, with HDMI 2.1's faster data transfer and higher bandwidth, lip-sync between audio and video will be even more accurate.
Control Center supports the HDMI 2.0 standard so it does not yet support eARC.
For more information on ARC please see article AUDIO: ARC