gipilot
With the exception of the UK where a recent court case went against the company, tax for based pilots is for based pilots to worry about. You must budget for it each month your pay packet arrives in your bank account. CX doesn’t withhold any income tax for you.
As some advice, you will pay tax in Hong Kong and in the EU country you reside in. If that country has a tax treaty with Hong Kong (most of them do), you will get a tax credit on the tax paid in Hong Kong against the tax you will have to pay in Europe.