Absolutely nothing, not one penny of this will be included in your 2019 return. If the improvements are completed in 2020 ***AND*** the improvements are placed "in service" in 2020, then when you complete your 2020 tax return in 2021 you will add your property improvements in the Assets/Depreciation section and depreciate them over the next 27.5 years from the date the asset was placed "in service" as a rental asset.
