here's a thread that should help with what tax equalization is. remember this is written from an employer's perspective.
https://arcrelocation.com/tax-equalization/
you might incur a higher tax obligation because of the way taxes work in the US and foreign country. the supposed benefit is that the employer takes on that added tax responsibility so you do not pay any more in taxes than you would if you were only working in the US - your home country.
negative - the worst would be that they are unable, unwilling, or legally able to escape the obligation leaving you holding the bag as they say
you may want more info from your employer such as an illustration of what they do and what you need to do and the financial aspect of thee.
you may even want to consult a lawyer