PTHLH and cancer: PTHrP is a well-known factor for malignancy-induced hypercalcemia and tumor-bone interactions in breast cancer bone metastasis30,31; thus, anti-PTHrP antibodies have long been used to suppress cancer progression and metastasis.32–35 However, anti-PTHrP antibodies have never been tested in combination with immune checkpoint inhibitors in cancer patients or murine tumor models, which is an important direction for further studies.