The disclosure provides methods of treating, identifying and/or selecting for treatment a subject having a cancer in which an immune checkpoint protein is upregulated. In certain embodiments, the methods for treating cancer in a subject in need thereof comprise administering to the subject: (a) a therapeutically effective amount of an EZH2 inhibitor and (b) a therapeutically effective amount of an immune checkpoint inhibitor. In certain embodiments of the methods of the disclosure, the EZH2 inhibitor is tazemetostat.