Pucotenlimab (Puyouheng™) is a humanised immunoglobulin (Ig) G4 monoclonal antibody (mAb) being developed by Lepu Biopharma for the treatment of solid tumours, including gastrointestinal cancer, metastatic melanoma, liver cancer, bladder cancer, non-small cell lung cancer and breast cancer. Pucotenlimab binds to PD-1 and blocks its interaction with its ligands, PD-L1 and PD-L2, thereby restoring the ability of immune cells to target cancer cells. In July 2022, pucotenlimab received conditional first approval in China for the treatment of patients with unresectable or metastatic microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) solid tumours, including patients with advanced colorectal cancer who have experienced disease progression after previous therapy with fluorouracil, oxaliplatin and irinotecan, as well as patients with other advanced solid tumours who have experienced disease progression after previous first-line therapy and have no satisfactory treatment alternatives. In September 2022, pucotenlimab was approved in China for the treatment of unresectable or metastatic melanomas after the failure of previous systemic therapy. This article summarizes the milestones in the development of pucotenlimab leading to the first approval for the treatment of MSI-H/dMMR advanced solid tumours.