Combining RT with immunotherapy (especially anti-PD-1/PD-L1 agents) has increased AE occurrences, though questions remain about this approach, particularly in tumors with low immunogenicity such as thymic squamous cell carcinoma (TSCC).<h4>Case description</h4>A 73-year-old woman with advanced TSCC and multiple metastases experienced disease progression after two therapies. The gene discussed is CD274; the disease is thymus squamous cell carcinoma.