Let G$G$ be a finite group. Atiyah proved that the K$K$-cohomology of BG$BG$ vanishes in odd degrees and in even degrees is the completion of the representation ring of G$G$ at the augmentation ideal.
What is the K$K$-homology of BG$BG$? I mean the stable homotopy groups of the complex K$K$-theory spectrum smash BG$BG$.