The three groups — which Sophos calls Cluster Alpha, Cluster Bravo and Cluster Charlie — each have ties to Chinese state-backed groups previously identified by other companies and governments - including APT15 and a subgroup of APT41 known by some researchers as “Earth Longzhi.”
https://therecord.media/tag/apt41
https://therecord.media/apt15-nickel-graphican-backdoor
The report follows up on one released in June about attacks on an unnamed government organization.