PurposeOur aim is to describe the role of immune checkpoint inhibitors (ICI) in clinical practice by providing the patient and tumor characteristics as well as survival and toxicity rates by sex.MethodsWe used electronic health records to identify patients treated at the Cancer Center of the University Hospital Bern, Switzerland between January 1, 2017 and June 16, 2021.ResultsWe identified 5109 patients, 689 of whom (13.5%) received at least one dose of ICI. The fraction of patients who were prescribed ICI increased from 8.6% in 2017 to 22.9% in 2021. ICI represented 13.2% of the anticancer treatments in 2017 and increased to 28.2% in 2021. The majority of patients were male (68.7%), who were older than the female patients (median age 67 vs. 61 years). Over time, adjuvant and first line treatments increased for both sexes. Lung cancer and melanoma were the most common cancer types in males and females. The incidence of irAEs was higher among females (38.4% vs. 28.1%) and lead more often to treatment discontination in females than in males (21.1% vs. 16.8%). Independent of sex, the occurrence of irAEs was associated with greater median overall survival (OS, not reached vs. 1.1 years). Female patients had a longer median OS than males (1.9 vs. 1.5 years).ConclusionsICI play an increasingly important role in oncology. irAEs are more frequent in female patients and are associated with a longer OS. More research is needed to understand the association between patient sex and toxicity and survival.