H1-B is a dual intent visa, so someone on one could be either an expat or an immigrant. I get the impression that it is more common for them to be immigrants be

H1-B is a dual intent visa, so someone on one could be either an expat or an immigrant. I get the impression that it is more common for them to be immigrants because someone who already worked for the company sending them to the US could get an L1 visa instead, which doesn't have the cap on number issued like H1-B does.