cancers Review Primary and Acquired Resistance to Immunotherapy in Lung Cancer: Unveiling the Mechanisms Underlying of Immune Checkpoint Blockade Therapy Laura Boyero 1 , Amparo Sánchez-Gastaldo 2, Miriam Alonso 2, 1 1,2,3, , 1,2, , José Francisco Noguera-Uclés , Sonia Molina-Pinelo * y and Reyes Bernabé-Caro * y 1 Institute of Biomedicine of Seville (IBiS) (HUVR, CSIC, Universidad de Sevilla), 41013 Seville, Spain;
[email protected] (L.B.);
[email protected] (J.F.N.-U.) 2 Medical Oncology Department, Hospital Universitario Virgen del Rocio, 41013 Seville, Spain;
[email protected] (A.S.-G.);
[email protected] (M.A.) 3 Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), 28029 Madrid, Spain * Correspondence:
[email protected] (S.M.-P.);
[email protected] (R.B.-C.) These authors contributed equally to this work. y Received: 16 November 2020; Accepted: 9 December 2020; Published: 11 December 2020 Simple Summary: Immuno-oncology has redefined the treatment of lung cancer, with the ultimate goal being the reactivation of the anti-tumor immune response. This has led to the development of several therapeutic strategies focused in this direction. However, a high percentage of lung cancer patients do not respond to these therapies or their responses are transient. Here, we summarized the impact of immunotherapy on lung cancer patients in the latest clinical trials conducted on this disease. As well as the mechanisms of primary and acquired resistance to immunotherapy in this disease. Abstract: After several decades without maintained responses or long-term survival of patients with lung cancer, novel therapies have emerged as a hopeful milestone in this research field.