Core Viewpoint - Immunotherapy, particularly immune checkpoint blockade (ICB), has transformed cancer treatment but remains ineffective in "cold tumors" due to immune suppression in the tumor microenvironment (TME) [2][5][6] Group 1: Research Findings - A new biomimetic Ru/TiO₂ nanobiocatalyst system inspired by natural enzyme reaction systems (ERS) has been developed, capable of rapid, pH-dependent generation of reactive oxygen species (ROS) and oxygen (O₂), effectively converting cold tumors into hot tumors [3][6][7] - The Ru/TiO₂ system enhances anti-tumor immunity and suppresses tumor metastasis when used in conjunction with ICB therapy [3][7] - This research establishes a precedent for adaptive nanobiocatalysts in the TME and paves the way for the development of next-generation immunotherapies targeting drug-resistant cancers [3][6] Group 2: Mechanism of Action - The study demonstrates that Ru/TiO₂ can mediate immunogenic cell death (ICD) in melanoma cells through endoplasmic reticulum stress, while also inhibiting hypoxia-induced immune suppression [7] - The design of Ru/TiO₂ aims to reverse immune suppression and enhance immunogenicity, transforming "immune cold" tumors into "immune hot" tumors [7] Group 3: Clinical Implications - The findings suggest that the rational design of robust and efficient biocatalytic materials could extend beyond cancer treatment, opening new avenues for immune modulation in other diseases [3][6]