CD274 and undifferentiated pleomorphic sarcoma: Based on T cell RNA sequencing, Pollack et al. reported the highest level of T cell infiltration in undifferentiated pleomorphic sarcoma, whereas synovial sarcoma had the lowest, and significantly higher levels of PD-L1 and PD-1 were observed in undifferentiated pleomorphic sarcoma compared to synovial sarcoma [38].