Few things that were mentioned on Chaincode's website:
Chaincode engineers develop, review, test and maintain Bitcoin Core
Chaincode has contributed research and design for many of the recent improvements in the Bitcoin protocol, e.g. Erlay and Compact Blocks.
The Chaincode Residency is a program for engineers to develop experience with Bitcoin. Chaincode has hosted several residencies focused on the Bitcoin protocol, Bitcoin Core, Lightning Network applications and the Lightning protocol.
Bitcoin Optech helps Bitcoin users and businesses integrate scaling technologies through workshops, documentation, weekly newsletters, original research, case studies and announcements.
The Chaincode Podcast brings you interviews with the most influential Bitcoin engineers about Bitcoin protocol development.
https://chaincode.com/projects