These are: Cognition, Culture, Content, Communication.
Any particular CLIL model or methodology needs to consider the relative value/importance of the parameters above.
This framework consists of 4 dimensions: Content (subject matter), Communication (learning through interaction), Cognition (learning and thinking processes), and Culture (intercultural understanding and global awareness in building up cooperation in learning).
To sum up, all four key principles (4Cs) of CLIL: cognition, content, communication, and culture, and CLIL models should be mastered by the teacher in order to design the learning strategies and the materials.