Pokemon Go is built on the same engine as Inverness I think its called. When it launched they even used the same POIs. I think this was ~5-7 years before PGO launched.
Edit: I said inverness and meant ingress. Apologies.
Famously for a long time, the best way to get a point of interest into PGO was to play ingress and request it's addition there
Pokemon Go was launched on the Unity game engine in 2016. Ingress was using a different game engine at the time, and wasn't rewritten into Unity until several years later. Even the backend/server side was significantly different, with them needing to write a shim to ensure compatibility during & after the move to Unity.
I think you are thinking of Ingress. No idea what Inverness is.
Ingress and PGO share the same portals and stuffs and its what PGO got its data from.