Analyzes of transcriptomic and clinical data from multiple cohorts of cancer patients receiving immunotherapy have shown that PD-1 blockade enhances tumor-specific plasma cell responses to IgG1. These humoral IgG1 responses to tumor antigens complement cellular immunity. They support clinical results in immune checkpoint blockade. The study was published in Nature Medicine online on January 27, 2026 with doi:10.1038/s41591-025-04177-6. The main finding is that these IgG1 responses contribute to the clinical benefit of immunotherapy.