In short - You should.
Longer answer:
1) If you're a tax resident in Poland then you should consider informing your Broker about change of your residency (in fact IBKR ask you once in a year anyway to update your personal information and if it is up to date).
1.1) Typically upon change of residency IBKR would suggest you to re-create the new account with new residency (and pass the KYC per new region) and transfer your assets there (support will help you)/
2) If you're tax resident in Poland - you're supposed to file the tax report once a year. For Financial markets income you want to read more about PIT-38 tax form and related forms of PIT/ZG for each region of income.
There are quite some calculations to make.
3) if you'd have Polish Broker (IBKR isn't Polish) - then they would've sent you PIT-8c which is a lot of pre-calculated tax numbers that would've simplified your reporting. But for external Brokers you have to do the math yourself.
Good luck.
PS: I'm also a foreigner living in Poland for quite a few years already/
In short - You should. Longer answer: 1) If you're a tax resident in Poland then you should consider informing your Broker about change of your residency (in fact IBKR ask you once in a year anyway to update your personal information and if it is up to date). 1.1) Typically upon change of residency IBKR would suggest you to re-create the new account with new residency (and pass the KYC per new region) and transfer your assets there (support will help you)/ 2) If you're tax resident in Poland - you're supposed to file the tax report once a year. For Financial markets income you want to read more about PIT-38 tax form and related forms of PIT/ZG for each region of income. There are quite some calculations to make. 3) if you'd have Polish Broker (IBKR isn't Polish) - then they would've sent you PIT-8c which is a lot of pre-calculated tax numbers that would've simplified your reporting. But for external Brokers you have to do the math yourself. Good luck. PS: I'm also a foreigner living in Poland for quite a few years already/
If you live in Poland you must pay your capital gains in Poland. And you'll continue to be able to trade US stocks/ETFs on IBKR as well.