For clarification regarding documents necessary to obtain entry into Canada: for PRs a PR card is NOT necessary to enter Canada.
A valid PR Card is still necessary to enter Canada . . .
A Canadian Permanent Resident is
entitled to enter Canada regardless any particular documentation. For purposes of the entry examination of a Canadian PR at a PoE, the PR card is the preferred status document, but is
NOT a necessary document, for establishing the traveler's status in Canada.
That is, a valid PR card is
NOT necessary for a PR to enter Canada.
Note, in particular for example, an
expired (not valid) PR card will readily and sufficiently establish a PR's status when presented at a PoE. (It will NOT suffice, however, for purposes of obtaining permission to board a flight to Canada.)
In the absence of any PR card (valid or expired), the process of verifying a traveler's PR status (for purposes of an entry examination at a PoE) can lead to some delay in the examination, depending on the nature and quality of documents the traveler presents to, foremost, establish identity. A CoPR or a copy of the CoPR in conjunction with documents establishing identity will typically facilitate the verification of status with minimal delay. Any CIC/IRCC document, even a routine letter from CIC or IRCC, showing the PR's name and client number will also help facilitate verification of status. With some exceptions, establishing identity itself will ultimately suffice. But again, a PR card, valid or expired, is not necessary for a PR to enter Canada.
Even if the OP is stateless, the OP should have other documentation of identity.
An observation about PR cards and travel documents:
I am not familiar with what a stateless person needs or can use as a Travel Document, or what other countries require of such travelers.
Generally, however,
a PR card is not a Travel Document. It is a Status Document. Even for purposes of boarding a flight to Canada, a PR ordinarily needs a valid Travel Document (typically but not exclusively a valid passport) in
conjunction with the PR card in order to obtain permission to board the flight.
There may be countries which recognize the PR card for this or that purpose, perhaps even as a Travel Document. That depends on that particular country's laws and policies. That is unlike the Canadian passport, regarding which international treaties and conventions mandate its recognition as a Travel Document by other countries (with exceptions; for example, the U.S. will not recognize a Canadian passport as a valid travel document if the traveler is known to be a U.S. citizen, even though in particular instances U.S. border authorities might recognize the Canadian passport as sufficient documentation of identity, including for purposes of allowing entry).
There are also countries, including the U.S., which will recognize Canadian PR
status for various immigration purposes. This too is specifically a matter of the other country's laws and policies. This can range from PR status entitling the traveler to certain status (such as a tourist or visitor visa) to merely being a positive factor or consideration in determining whether to allow the traveler entry status. In this context the PR card documents the PR's
status, and that is what matters (recognizing that implementation in a particular country may be conditioned on possession and presentation of a valid PR card as proof of such status).
Overall take-away:
PR cards have rather limited use. They are not a Travel Document. They are a Status Document. Their primary use is to establish authority to enter Canada for the purpose of obtaining permission to board a flight to Canada (but even for this, ordinarily a PR card is not sufficient, the traveler still needs a valid Travel Document). They are the primary, preferred proof of status in a PoE examination but are
NOT necessary to obtain entry into Canada. Beyond that, Provincial and Federal agencies may require a PR card to show Canadian status in certain transactions, such as applications for benefits, including a health care card, or a drivers' license. While banks may ask for the PR card when a person opens a new bank account, ordinarily an individual can provide alternative documentation for this.
While international treaties and agreements and conventions govern recognition of certain Travel Documents, including passports from almost all recognized national governments, for purposes of travel to any particular country what constitutes a recognized and valid Travel Document is dictated by the laws and policies of each individual country (subject to that country's obligations pursuant to regional international organizations, such as countries in the EU) .