The.calling.s01e06.1080p.web.h264(cm).mp4 -

Likely a tag for the specific release group or internal encoding identifier.

The video compression codec used (Advanced Video Coding). The.Calling.S01E06.1080p.WEB.H264(CM).mp4

Indicates the source material was ripped from a streaming service (e.g., Peacock). Likely a tag for the specific release group