Are the shooting scenes of American TV series all shot globally or in a certain film and television base?

The shooting of American TV series is a balance between plot needs and cost. Consider the most suitable scenario and the most balanced local government subsidies to find the best solution. If you need a forest cabin, you can rent it. If you need city roads, you can shoot in the street (you need to apply for permission). If the cost does not allow, you can go to the "film and television base" or similar places, or you can temporarily set up a backstage.

Most American TV shows were shot on the set of Universal Studios in burbank. If they are in the east, they usually shoot in new york.

Like Game of Thrones, filming in Spain, Morocco, Northern Ireland, Scotland, Malta and Iceland is a few exceptions.