Kenopanishad belongs to the Saamveda, talavakara shakha. It essentially deals with nature of Brahman and establishes that this highest Truth does not come under the scope of ordinary means of knowledge in a human mind.This Upanishad is divided into 4 khands- the first 2 khand is in pursuit of the nature of Brahman. The 3rd and 4th khand reiterates the nature of Brahman in a story form. This makes the Upanishad unique in the sense that it speaks of Ishwara and Avatar. 

An in-depth analysis of Shankara Bhashya outlining the essential principles along with Ishwara prakaran has been beautifully expounded by Pujya Swamiji.