PDCD1 and pneumonitis: Risk factors for pneumonitis that have been described include: a poor ECOG performance status, smoking with a cumulative dose greater than 50 pack-years, pulmonary neoplasia [23,36], the presence of autoimmune disease [27], previous pulmonary disease (asthma, chronic obstructive pulmonary disease -COPD-, interstitial lung disease -ILD-), a history of thoracic radiotherapy, PD-1 inhibitors, and the combination of different ICIs and ICIs with chemotherapy [24].