a Three different mechanisms by which small molecules might enhance anti-tumor T-cell function: (1) upregulate biosynthesis/secretion of anti-tumor cytokines (e.g., IFNg, TNFa), (2) increase production/secretion of T-cell cytolytic granules or perforin proteins or (3) upregulate antigen processing/presentation on tumor cells. b Workflow of IO screening platform. Human HLA-A02 PBMCs are isolated and cultured in the presence of CEF viral peptides (day −9). Activated T-cells are expanded first in IL-2 (2 days), then in IL-2, IL-4, and IL-7 (4 days) to generate the desired memory T-cell population. Human HCT116-EGFP colorectal cancer cells are dispensed into 1536-well spheroid plates (day −2) and on day 0 T-cells are stained red and added to spheroid cultures. Experimental compounds are added and co-cultures are incubated for 3 days before the first imaging read and then a further 2 days before the final imaging read.