Canada and America are both multi-ethnic, multi-racial societies, based on the principles of representative democracy. While Canada has Parliament, the U.S. has Congress, but they function in a similar fashion. Canada, of course, still pays homage to the Queen, but, as is true in every modern society, the monarchy is the titular head of government only, not a functioning part of the actual governing system.
Canadians and Americans share many aspects of their cultures and have been each other's major trade partners for many decades. There is close cooperation between our military establishments, including mutual assistance in our space programs.
The U.S. and Canada have been allies in every war since the turn of the twentieth century, although our governments have not always agreed on strategy and tactics. Canada has always been more favorable to a diplomatic approach than has the U.S.
We tend to like the same movies, watch the same TV shows, and listen to the same music. Basically, we share a common language that is much closer than Canadian English and British English or American English and British English. Of course, Canada is technically bi-lingual, although French is used mainly in Quebec. The U.S. has a great many Spanish speakers, not just in the Southwest (Mexican Americans), but also in and around Florida (Cuban Americans), and New York (Puerto Rican Americans).
I've been to about half of the states and three provinces of Canada, and I've observed far more similarities between the two nations than differences.