Using murine organotypic tumor spheroids from MC38luc colorectal cancers to replicate the tumor microenvironment (TME), CLF synergized with anti-PD-1 + CTLA-4 ICB to substantially improve tumor responses across melanoma, lymphoma, and lung cancer models, and in vivo studies highlighted an 80% tumor-free survival rate in the hypermutated MC38 model, surpassing ICB alone. Here, CTLA4 is linked to melanoma.