This study presents a novel approach to enhance anti-tumor immunity by utilizing engineered algae microrobots. The researchers developed a living biomaterial by coating photosynthetic *Chlorella vulgaris* microalgae with a genetically engineered dendritic cell (DC) membrane overexpressing immunostimulatory TNF ligand proteins, including OX40L, 4-1BBL, and CD70. This "photosynthetic micron robot" generates oxygen in situ, alleviating hypoxia in the tumor microenvironment and thereby improving the activation and proliferation of T cells. The TNF ligand proteins on the surface of the microrobot bind to their cognate receptors on T cells, enhancing their activity and promoting the formation of memory T cells. When combined with a PD-1 inhibitor, the microrobot significantly prevents tumor relapse and metastasis in mice. The study demonstrates that the engineered algae microrobot not only alleviates hypoxia but also enhances T cell function, leading to improved immunotherapy outcomes. The results suggest that this approach could be a promising strategy for cancer immunotherapy by effectively targeting the tumor microenvironment and enhancing the immune response against cancer.This study presents a novel approach to enhance anti-tumor immunity by utilizing engineered algae microrobots. The researchers developed a living biomaterial by coating photosynthetic *Chlorella vulgaris* microalgae with a genetically engineered dendritic cell (DC) membrane overexpressing immunostimulatory TNF ligand proteins, including OX40L, 4-1BBL, and CD70. This "photosynthetic micron robot" generates oxygen in situ, alleviating hypoxia in the tumor microenvironment and thereby improving the activation and proliferation of T cells. The TNF ligand proteins on the surface of the microrobot bind to their cognate receptors on T cells, enhancing their activity and promoting the formation of memory T cells. When combined with a PD-1 inhibitor, the microrobot significantly prevents tumor relapse and metastasis in mice. The study demonstrates that the engineered algae microrobot not only alleviates hypoxia but also enhances T cell function, leading to improved immunotherapy outcomes. The results suggest that this approach could be a promising strategy for cancer immunotherapy by effectively targeting the tumor microenvironment and enhancing the immune response against cancer.