//Why is Boris at Davos!//
The same can be asked of Sir Anthony Charles Lynton Blair. The answer is that Davos is a preening exhibition of people (mainly of whom few people have ever heard) who fly there in private jets and pontificate to the little people about the alleged dangers of climate change.
In Sir Blair's case he is also setting out CV for the top job when the current president, Børge Brende, turns it in. This has become necessary now that his opportunities for a place at the top trough within the EU have been somewhat scotched.
I imagine Mr Johnson is there to keep his contact list up to date. Whether he would wish to be involved in such a farce is another question.