Background: There is a need for a better understanding of survivorship-related issues in advanced cancer survivors treated with immune checkpoint blockade (ICB). The purpose of this study was to identify survivorship-related issues, with a focus on psychological distress, cognitive complaints, physical sequelae, impact on family dynamics, and care needs in unresectable, advanced cancer survivors treated with ICB. Methods: Semi-structured interviews and patient-reported outcome measures (PROMs) were conducted in survivors followed up at the University Hospital Brussels. We performed content analysis on the semi-structured interviews and analyzed the PROMs descriptively. Results: 70 cancer survivors (71.4%) consented to participate between July 2022 and November 2023. Clinical fear of cancer recurrence (FCR) was present in 54.3% of the cancer survivors, and 18.6% had elevated cognitive complaints. We identified triggers related to clinically important psychological distress, such as immune-related adverse events, the progression/recurrence of disease, difficulties in adjusting to life after treatment, and co-existing life stressors, alongside persistent physical issues and unmet psychological and nutritional care needs. Conclusion: Our results indicate the existence of persistent psychological, physical, and cognitive issues, and support the need for routine screening for FCR. The identified triggers related to severe psychological distress can aid clinicians in timely referring the patient, thereby enhancing survivorship care.