Primary thoracic cancers affect a large number of patients, mainly those with lung cancer and to a lesser extent those with pleural mesothelioma and thymic tumours. Given their frequency and associated comorbidities, in patients whose mean age is high, these diseases are associated with multiple complications. This article, the last of a series dedicated to emergencies in onco-haematological patients, aims to present a clinical picture of the severe complications (side effects, immune-related adverse events) associated with systemic treatments, excluding infections and respiratory emergencies, with which general practitioners and specialists can be confronted. New toxicities are to be expected with the implementation of innovative therapeutic approaches, such as CAR-T cells, along with immunomodulators and antibody-drug conjugates.