The CBOR WG has produced STD94, the main CBOR specification: https://datatracker.ietf.org/doc/std94/
Ongoing work includes work on deterministic/distinguished/distinct/restricted encodings which are subsets of the most general specification, updates to the Diagnostic Notation --- the Extended Diagnostic Notation, and extensions to the CDDL https://www.rfc-editor.org/info/rfc8610
There are some topic-specific wiki associated with some documents: