PDCD1 and cancer: Wargo et al. (Gopalakrishnan et al., 2018) at the MD Anderson Cancer Center explored Faecalibacterium species enriched in R patients by 16S rRNA gene sequencing in 25 samples from melanoma patients treated with anti-PD1 (Vétizou et al., 2015; Gopalakrishnan et al., 2018).