And a pardon usually includes an admission of guilt.
When a president pardons a scoundrel many citizens think "The bum/rat got off with a pardon."
But does a pardonee merit escape of all opprobrium for their misdeed(s)?
They do not because a pardon "carries an imputation of guilt; acceptance a confession of it."
Burdick is an apposite case.
BURDICK v. UNITED STATES (1915)
This brings us to the differences between legislative immunity and a pardon. They are substantial. the latter carries an imputation of guilt; acceptance a confession of it. The former has no such imputation or confession. It is tantamount to the silence of the witness. It is noncommittal. It is the unobtrusive act of the law given protection against a sinister use of his testimony, not like a pardon, requiring him to confess his guilt in order to avoid a conviction of it.