Market and exchanges

I don't remember where, but I've seen something about the possibility of making exchanges in PGO... Does somebody know if there will be such a possibility, and about what? Pokemons? Items?

Right now I have many evolution items which are quite unuseful since I won't use them but I'm keeping them for this reason, maybe one day I will use them to have some more useful items...

Does anybody know if such an option will be added?