I am someone who has immigrated to both countries. Originally from India, I moved to the US for graduate studies. I was on H1B, got a green card and eventually became a citizen.
In 2010, my academic career brought me to Canada as a teacher tenured professor at the University of Toronto. In the course of time here, we have become Canadian PRs and eventually citizens. I am a US Canada dual citizen, and also hold an OCI (overseas citizen of India) card.