Although the immune system has a milieu of inhibitory receptors to limit excessive T cell-mediated inflammatory responses, cancer cells have evolved to seize those inhibitory pathways and to prevent T cell-mediated killing of tumor cells. Therefore, immune checkpoint inhibitors (ICI) are consisted of blocking antibodies against these receptors and have been promising means of inhibiting immune system tolerance to tumors and thus rescue exhausted antitumor T cells. At Creative Biolabs, we have developed streamlined protocols for efficient delivery of ICI agents by viral vectors. Various vectors have been engineered to express antibodies targeting CTLA-4, PD1, PD-L1 or Tim3, etc. GTOnco™ platform also provides preclinical validation of the recombinant immuno-oncology products.