Recently, another study examined the fecal specimens of metastatic melanoma cases prior to PD‐1 blockade cancer treatment, and demonstrated that abundance of C. aerofaciens, E. faecium, and B. longum were higher in the PD‐1 blockade immunotherapy responders, underpinning the antitumor actions of such microbes.70 Here, PDCD1 is linked to cancer.