Disclosed herein are methods of treating or assessing cancer in a subject wherein it has been determined whether the cancer comprises a loss of function mutation or disruption in an immune pathway. The loss of function mutation or disruption can be in JAK1 or JAK2. The loss of function mutation or disruption can be in B2M. The methods can include administering an immune checkpoint therapy such as anti-PD1 or anti-PDL1. The methods can include administering an alternative therapy to an immune checkpoint therapy. In some aspects, the method includes determining whether the cancer comprises a loss of function mutation or disruption in an immune pathway.