"can't wait to do sth" vs "can't wait doing sth"

English as a Second Language English Vocabulary, Grammar and Idioms
1

what is the difference between “can’t wait to do sth” and “can’t wait doing sth” ?
Any message from you will be appreciated.

2

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I understand as below:

can’t wait to do sth - more importance for ’ to do ’

can’t wait doing sth - more importance for ’ sth ’

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