This news might be a month old, but is a great example of outdoor advertising for game companies. I'm not sure if Zynga, Kabam or Supercell did anything like this in San Francisco. But here in Hong Kong, the talk is all about Tower of Saviors - a gem matching game that runs deep with a card collections mechanic combined with a very appealing combat system.
Madhead (makers of ToS) got a well known local actress to star in all the outdoor ads - tram stops, busses and billboards to name a few. At this scale, i have no clue what the ROI is, but if they don't make it up in terms of dollars, they sure got the brand out. Kudos to the team.