tax implementation if leaving the US

Possibly. How long have you been here?  If you have been a resident of the United States for more than 10 years, then you would be considered a covered expatriate. 

If you are a long term resident, you may be subject to the tax if any of the following apply to you 

• Your average annual net income tax for the 5 years ending before the date of expatriation or termination of residency is more than a specified amount that is adjusted for inflation ($162,000 for 2017, $165,000 for 2018, $168,000 for 2019, $171,000 for 2020, $172,000 for 2021, $178,000 for 2022, and $190,000 for 2023).
• Your net worth is $2 million or more on the date of your expatriation or termination of residency.
• You fail to certify on Form 8854 that you have complied with all U.S. federal tax obligations for the 5 years preceding the date of your expatriation or termination of residency.