U.S. citizens and residents must pay tax on their worldwide income. There is a limited exclusion for earned income (up to $103,900 in 2018), but there is no exclusion for gain on the sale of property abroad.
Costs that are not currently deductible and that are added to the basis of property. A capital expense generally increases the value of property. When added to depreciable property, the cost is deductible over the life of the asset.