Google Maps SDK for iOS requires GoogleMaps.bundle to be part of your target under ‘Copy Bundle Resources

The instructions are kinda lacking.

1. Launch Xcode (easy)

2. Drag the GoogleMaps.framework bundle to the Frameworks
   group of your project. When prompted, select Copy items into
   destination group’s folder.

3. Right-click GoogleMaps.framework in your project, and select Show In
   Finder. What it doesn’t say is…Then go into the child folder called Resources

4. Drag the GoogleMaps.bundle from the Resources folder to your
   project. We suggest putting it in the Frameworks group. When
   prompted, ensure Copy items into destination group’s folder is not
   selected.