In one aspect, provided herein is a method comprising: (a) (i) determining cytolytic activity in a tumor from the subject; and/or (ii) determining genetic alterations associated with cytolytic activity in the tumor; and (b) administering an immunotherapeutic agent to the subject if (i) cytolytic activity is detected in the tumor and/or (ii) a genetic alteration associated with induction of cytolytic activity, tumor resistance to cytolytic activity and/or suppression of cytolytic activity is detected in the tumor.