PDCD1 and melanoma: A phase I clinical trial has demonstrated that utomilumab is well tolerated by patients with advanced tumors; its irAEs are <10%, and the overall ORR is 3.8% in solid tumors; however, the therapeutic effect of combining utomilumab with other ICIs such as pembrolizumab remains to be explored, along with the application potential of single-agent umilumab in melanoma and NSCLC, which are cancer types that are resistant to anti-PD-1/PD-L1 therapy (135).