Disclosed herein are methods for use in treating cancer comprising administering at least one cancer sternness inhibitor, for example, at least one STAT3 pathway inhibitor such as 2-acetylnaphtho [2, 3-b] furan-4, 9-dione, in order to sensitize or re-sensitive a cancer that is naive, resistant, or/and refractory to at least one immunotherapeutic agent, such as at least one immune checkpoint modulator.