PDCD1 and telomere syndrome: Tumor immunotherapy has become a research hotspot, and tumor immune escape has been recognized as a hallmark of tumorigenesis.[23] The therapeutic method of exerting an anti-tumor effect by manipulating the immune system is very promising, especially the blocking treatment of 3 immune checkpoints: CTLA-4, PD-1, and PD-L1 has achieved great success in tumor treatment and therapy, such as cutaneous melanoma, non-small-cell lung cancer, clear cell cancer, and hematological malignancies.[24] However, not every STS patient is sensitive to immunotherapy.