Some data about immigration to Poland:
https://migracje.gov.pl/en/
There is also this thing called Karta Polaka, Polish Card, Polen-Karte:
https://en.wikipedia.org/wiki/Karta_Polaka
From Wikipedia: Polish Card, is a document confirming belonging to the Polish nation, which may be given to individuals who cannot obtain dual citizenship in their own countries while belonging to the Polish nation according to conditions defined by law; and, who do not have prior Polish citizenship or permission to reside in Poland. It was established by an act of the Polish parliament dated 7 September 2007 called the Act on the Pole's Card (Ustawa o Karcie Polaka, Dz.U. 2007 no. 180/1280), which specifies the rights of the holder of the Card, the rules for granting, loss of validity and rescission of the Card, and the competencies of the public administration's bodies and procedures in these cases. The law came into force on 29 March 2008.
The Card can be granted to a person who declares "belonging to the Polish nation" and
meets the following conditions:
1) Proves his/hers relationship with Polishness by at least a basic knowledge of the Polish language, along with knowledge and cultivating Polish traditions and habits;
2) In the presence of the consul of the Republic of Poland or an authorized employee of a Polish organisation submits a written declaration of belonging to "the Polish Nation";
3) Proves that at least one of his/her parents or grandparents or two great grandparents were of Polish nationality [= national identity] or had Polish citizenship, or present an attestation from a Polish or Polish diaspora organization acting on the territory of one of the above mentioned states, confirming that he or she has been actively involved in Polish linguistic and cultural activities within Polish community of their region for a period of at least the past three years.
^^^ So having "ethnically Polish" ancestry is not even among required conditions to obtain such Polish Card.
You can get it based on your willingness to live in Poland and having knowledge of the language and culture.
For example a Polish Jew living in Israel with ancestry from Poland might also be eligible to get this card.
But check the map below:
States whose citizens of Polish origin may apply for the Karta Polaka (red), as of 29 March 2008:
https://upload.wikimedia.org/wikipe...px-Location_Polish_Charter_29_03_2008.svg.png
For some reason, we issue Polish Cards only to people in countries located to the East of us. I don't know why is this the case. In my opinion Poland should widen the scope and include also Germany, Czechia, France, Slovakia, Israel, the USA, Canada, Brazil, South Africa, etc. All places where people with ancestry from modern and historic Polish lands can be found.
Why does our law discriminate against people with Polish identity from these countries? When Poland first introduced Karta Polaka, Lithuanians complained that this Polish law violates the equality of legal entities in European Union's territory, because citizens of the Baltic states could obtain Karta Polaka, but Polish communities in France or Germany could not.
And I have to admit that Lithuanians are absolutely right in this case, it is offensive to their country that this law is specifically targeted at them (plus a few more countries) and not at all countries where Polish communities or people with ancestry from Poland can be found.
Technically, Karta Polaka is most useful for people from outside the EU. For inhabitants of the EU it is less useful because people with European Union's citizenship have a wide scope of rights in Poland anyway (even without having a Polish citizenship). However, we already offer Polish Cards to citizens of 3 EU states - Lithuania, Latvia and Estonia - so why not also to citizens of other EU states? This should be changed.
Originally, the idea of the Polish Card was invented for people who live in countries which do not allow dual citizenship (or where obtaining dual citizenship is very hard), so that they could get a Polish Card (easy solution) instead of trying to obtain Polish citizenship:
Dual citizenship laws by country:
https://www.dualcitizenship.com/bycountry.html
Global map:
https://qph.ec.quoracdn.net/main-qimg-145cdb0e45d735371b7881785eac83f2
Europe map: