U.S. citizens and residents are within the U.S. gift and estate regime wherever they live, and it rarely lines up with the rules of the country they live in. A transfer that is entirely untaxed locally can still carry a U.S. filing obligation.
Receiving from abroad
Receiving a gift or an inheritance from a non-U.S. person is generally not itself taxable to you as the recipient. Above certain thresholds it is nevertheless reportable, and that distinction is what catches people out: nothing is owed, and a return is still due.
Giving as a U.S. person
Gifts you make are measured first against an annual exclusion per recipient and then against a lifetime exemption. A transfer to a spouse who is not a U.S. citizen follows its own rules rather than the unlimited marital deduction most people assume applies.
Planning before a transfer is almost always cheaper than reporting one afterwards. If a gift or an inheritance is on the horizon, speak to us while it is still on the horizon.