Single-cell RNA sequencing of PBMCs from a patient with prolonged stable disease revealed dynamic shifts in monocyte and CD8 T cell phenotypes and inflammatory signalling pathways, which paralleled radiological tumour regression and subsequent progression.<h4>Discussion</h4>Our findings highlight peripheral immune profiles as candidate biomarkers for predicting and monitoring ICI efficacy in STS. The gene discussed is CD8A; the disease is neoplasm.