Many people have faced serious legal consequences for not answering questions from Congress, for example related to Jan. 6 riot. You do have the right to avoid

Many people have faced serious legal consequences for not answering questions from Congress, for example related to Jan. 6 riot. You do have the right to avoid testifying against yourself, so often Congress has to grant immunity from prosecution, in order to remove this legally justifiable excuse for not answering questions. I remember in the Iran/contra scandal, Congress was asked not to do this so that some of the people involved could be prosecuted, but chose to proceed for various reasons best known to themselves.