There are some countries where you can be 100 percent certain that you don’t have to pay income tax.
1- Qatar (no personal income tax)
2- Oman (no personal income or capital gains taxes)
3- United Arab Emirates (no personal income or capital gains taxes)
4- Saudi Arabia (no personal income tax)
5- Bahrain (no personal income tax)
6- Kuwait (no personal income tax)
7- Bermuda (no personal income tax)
8- Cayman Islands (no personal income or capital gains taxes)
9- Bahamas (no personal income tax)
10- Monaco (no personal income tax unless you’re French)
11- Hong Kong (no personal income or capital gains taxes)

https://www.telegraph.co.uk/expat/money/countries-that-dont-have-income-tax-in-pictures/