Methods for selecting a cancer patient for immunotherapy comprise establishing a total passenger gene mutation burden from a tumor of a cancer patient, generating a background distribution for the mutational burden of the tumor, normalizing the total passenger gene mutation burden against the background distribution, and categorizing the cancer patient as an immunotherapy responder when the total passenger gene mutation burden is greater than the mean of the background distribution. When the cancer patient is an immunotherapy responder, the patient may be administered an immunotherapy regimen that comprises activation/inhibition of T cell receptors that promote T cell activation and/or prolong immune cytolytic activities.