What would be a reason why the IRS is not charged my credit card for my tax payment yet?

The IRS doesn't process credit card payments.  That is outsourced to another company.

How did you make your payment?  Inside Turbotax when you e-filed?  When did you e-file?

I would start by contacting your CC bank, they might have blocked the transaction.  In that case, you can make a direct payment at www.irs.gov/payments.

Then, I would call Turbotax customer support and ask to verify that you did include the CC number on your e-file.  If you had a typo in the number or security code, the transaction would not go through.  You can make a direct payment instead.

But, I would be careful not to make an extra direct payment until you can verify that your intended payment failed, because if you make a payment and then the first payment goes through, it will take several weeks/months for the IRS to send the duplicate payment back.