PDCD1 and thoracic cancer: As first approvals of anti-PD-1/PD-L1 in SCLC and MPM and also results from early-phase trials have recently shown, combining ICIs with chemotherapy, different ICIs (such as those targeting CTLA4) or even with targeted therapies, might represent a valid solution to overcome resistance and to broaden the population of thoracic cancer patients who may benefit from immunotherapy.