Background and purpose: Palliative immune checkpoint inhibitor (pICI) treatment has improved overall survival (OS) in many solid tumours during the last decades. However, the survival benefits are based on fit patients included in the clinical trials, all with Eastern Cooperative Oncology Group Performance status (ECOG PS) 0-1. Data on survival in PS 2-3 patients are limited. This study aimed to compare OS according to ECOG PS at the initiation of pICI in real world data. Patient/material and methods: ICI has been recorded in the Swedish National Cancer Drug Registries since 2010. Palliative ICI treatment in the Southeastern region, Sweden, from 2010 until April 2025 were included. Survival probability and median overall survival (mOS) were calculated. Results: A total of 1956 patients had received at least one pICI treatment, for lung cancer (n = 854), melanoma (n = 443), renal carcinoma (n = 218) and urothelial carcinoma (n = 127). PS 2 or higher was reported in 28.9% and 80.6% received ICI only (no chemotherapy). mOS was in PS 0-1 patients 23.4 months, in PS 2 patients 9.6 months and in PS 3 patients 3.8 months. Death within 90 days occurred in 45.7% of PS 3 patients. Interpretation: Less fit patients are commonly treated with pICI, and PS seems an important predictive factor for palliative ICI regardless of cancer subtype. In our data, mOS is particularly short in PS 3 patients, suggesting to refrain from treatment. mOS is shorter in PS 2 patients than in PS 0-1, warranting individual considerations in treatment decisions. Better tools to guide treatment decisions for PS 2 patients are desirable.