When Woody Garfield is being followed after collecting the rental car, Inspector Deutsch uses the call-sign 'Inspector 71'. This is the same call-sign used by Harry Callahan in Dirty Harry (1971), which also takes place in San Francisco.
In In the Heat of the Night (1967) Virgil says he's not married, but in this sequel he is and has two children.
In In the Heat of the Night (1967) Virgil Tibbs was a detective from Philadelphia but in this sequel he is now a Lieutenant in San Francisco.