There are many such issues that matter to some extent for global human resource management.
For example, there are different tax laws in different countries. These affect the amount of money that various workers will have to pay. A US national working abroad may have different tax liabilities than one working in the US. It is necessary to adjust compensation to be sure that these issues are accounted for.
As another example, different countries will have very different laws about the rights of workers. Human resource managers must be aware, for example, of countries where workers are protected from being laid off or where they must be given certain levels of severance pay if they are laid off. These countries' more rigid labor markets must be taken into account when making decisions on staffing in those countries.