Tumour immunotherapy in solid and hematologic malignancies: Progress, challenges, and a practical framework

Tumour immunotherapy has reshaped the landscape of oncology by translating fundamental insights from immunosurveillance, immunoediting, and checkpoint biology into effective clinical strategies. This review traces the historical trajectory of tumour immunotherapy, from the early observations of William Coley to the development of modern immune checkpoint inhibitors (ICIs) targeting cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed cell death protein 1/ligand 1 (PD-1/PD-L1). Moreover, a comprehensive analysis of the progress of immunotherapy across different tumour types is provided. In solid tumours, significant benefits have been achieved in ``inflamed'' or ``hot'' cancers like melanoma, non-small-cell lung cancer, and renal cell carcinoma. However, formidable hurdles remain in ``non-inflamed'' or ``cold'' tumours such as pancreatic ductal adenocarcinoma, glioblastoma, and microsatellite-stable colorectal cancer. In hematologic malignancies, living drugs and redirecting immunotherapies have demonstrated profound efficacy: CAR-T therapy has achieved durable remissions in B-cell acute lymphoblastic leukemia (B-ALL) and diffuse large B-cell lymphoma (DLBCL), while T-cell engagers offer a rapid, ``off-the-shelf'' option for multiple myeloma. Collectively, this review synthesizes these developments into a practical framework based on tumour immune context, offering a guide for optimizing current treatments and directing future research to overcome resistance and benefit more patients.