Herbie Hancock, 86, has been among jazz’s most persuasive ambassadors for decades. Yet basking in the presence of the icon may not be the best reason to attend Hancock’s return to Muriel Kauffman Theatre on Thursday, August 6. The caliber of his band- trumpeter Terence Blanchard, guitarist Lionel Loueke, bassist James Genus and drummer Jaylen Petinaud- is explosive. The embedded video is pulled from a 52-year-old television appearance.