Please post a new question and include the date.
A date is needed. Please see the question "What is the value of a (date) US 20 dollar bill?" for more information.
$22 to $45 depending on condition
The star indicates it's a note printed to replace one that was damaged during the printing process. While some "star notes" can be moderately valuable, modern $20 bills are so common that the star may add only a couple of dollars at most.
Your bill is actually called a Federal Reserve Note, like modern $20 bills, rather than "a bank note of Chicago". Chicago is simply the Federal Reserve District location that distributed the bill. Please see the question "What is the value of a 1928 US 20 dollar Federal Reserve Note?" for more information.
The value is more dependent on the year (series) of the bill. The serial number by itself isn't enough information.
It's only worth $20 unless it's old.
The US didn't print any $20 bills dated 1920. Please check again post a new, separate question with more details.
20 dollars
A date is needed. Please see the question "What is the value of a (date) US 20 dollar bill?" for more information.
A star note would have a slight collector value above face value, but only if the bill is in crisp uncirculated condition. It's not old enough of a series to be worth more.
it is worth much more
It means the note is a replacement note, usually to correcy a printing error. This star does not mean the note is worth any more than the denomination printed on it
$22 to $45 depending on condition
The star indicates it's a note printed to replace one that was damaged during the printing process. While some "star notes" can be moderately valuable, modern $20 bills are so common that the star may add only a couple of dollars at most.
Your bill is actually called a Federal Reserve Note, like modern $20 bills, rather than "a bank note of Chicago". Chicago is simply the Federal Reserve District location that distributed the bill. Please see the question "What is the value of a 1928 US 20 dollar Federal Reserve Note?" for more information.
You say "5-star" - this works as an adjective, like "20-dollar note" or "5-day holiday".
The 1974 US $20 star note is valued in price close to $30 each. The amount will vary depending upon the condition the bill is in.