PDCD1 and melanoma: A. Muciniphila was shown to increase the abundance of gut-targeted CD4+ T cells, providing an adjuvant effect to the action of anti- programmed cell death -1 (PD-1) agents, in animal models of melanoma and non-small cell lung cancer (NSCLC) [65] and in a model of microsatellite-stable (MSS) colorectal cancer [66].