PvP has been announced and will be in game this year, which could mean christmas 2018…
Trading however, please not. Trading in the videogames is needed for evolving certain pokemon and getting otherwise unobtainable mons from the other games.
Both reasons are not applicable for PoGo. We can evolve them all and we can catch them all (providing some traveling). It only requires time (and money).
So, there is no need for trading.
Also, trading would make the game less interesting for many players, just trading their way up, but not playing. Not playing = less money earned by Niantic.
To sum it up: i don’t expect trading to ever come to poGo. Pvp, yes, it was announced for this year. Prediction: 2nd quarter of this year.