no title in netVisual_aggregate cellchat 加上 title(main = paste0(i,‘signaling‘))即可

   pdf("3.Sig_Pathway_Circle_Plot_.pdf")
  for(i in pathways){
    print(i)
    p = netVisual_aggregate(cellchat,show.legend = TRUE, 
                            signaling = i,signaling.name = paste(i,"sigaling"),
                            ,pt.title=10,vertex.receiver = vertex.receiver, layout = "circle") 
    title(main = paste0(i,'signaling'))
    print(p)
  }
  dev.off()