While the P365 is a solid (and popular) choice, there isn't "a" single preferred pistol. All the major manufacturers (i.e. Glock, SIG, S&W, Ruger etc.) make decent offerings. Much depends on your desires, wants, needs, limitations, capabilities, budget, etc. There isn't a single pistol for "concealed carry" since "concealed carry" isn't a single, monolithic thing.
Where did I say the 365 is the single preferred pistol?
My&P Shield 9mm. Just picked up some mag extenders that turn the 8-round mags into 10-rounds, from X tech Tactical.