* Payroll: how do I pay you, what's the frequency of payment in the region, how do deductions work, is overtime a thing?
* Working time: how many hours, how do I monitor the hours, do I have to give you breaks, do I have to document the breaks?
* Data protection: how do I ensure it, how do I send you the equipment you need, what happens if your device becomes non-compliant?
* Health Insurance: Does your country need it? How much does it cost? How much do I need to monitor it?
* Corporate law: by hiring you, have I established a legal entity in that country? Do I need to make a permanent entity in your country? How does profit attribution work in your country and what are the tax implications of hiring you?
* Personal taxes: Does your country and mine have some sort of double taxation agreement? What about social security type agreement? Who do I pay? Who do I tell that you are working there? What identification numbers do I need in order to tell them you work for me? How do they know who I am if I don't happen to have an entity in that country?
Honestly its just not worth the hassle for most situations. It's expensive, hard to do, complicated and creates all sorts of really difficult to account for edge cases when writing policies or attempting to enforce rules.