Context: Donald Trump spewing bullshit about annexing Canada and Greenland. Meanwhile, Congress has been dragging their feet for YEARS on resolving Puerto Rico's territorial status.
Citizens living in US territories do not receive equal representation in congress. For instance, PR has one "delegate" to the House (not an official voting member) and no senators. Taxation without representation.
Although, at this point I wouldn't blame PR if they changed their minds about wanting to become the 51st state.
They could become a Canadian province. We'd welcome them in, but wouldn't force them into it against their will.
It would make a lot of sense. Canada already has a province where the population doesn't speak English. And Canada would definitely appreciate a place with a tropical climate in a way the US never would. Plus, 3.2 million people is easy to ignore in a country of 330 million. But, in Canada they'd be the 5th biggest province, so they'd hold a lot of sway.
Or, at least, they could join the Commonwealth and have stronger relations with Canada, the UK, the Bahamas, Antigua and Barbuda, Jamaica, etc.