There aren't a whole lot of smartphones on the market that come with pens, despite Samsung being quite successful with its Galaxy Note series, which has been in production for nearly a decade. As uncovered by noted leakster Evan Blass, apparently Motorola is working on one too, although not much else is known about it.
It's not even Motorola's first pen-enabled phone in recent years. Last year's Moto Z4 actually came with support for N-Trig pens, such as Microsoft's Surface Pen. Obviously, it didn't ship with one though, let alone have one stored inside of the device. This device does seem to have a pen that will be stored internally, so it's not clear if Motorola is sticking to N-Trig, which usually comes in bigger pens that have batteries.
It's likely that this could end up being another device from the Motorola One lineup. Motorola One devices tend to be specialty handsets, that have one really interesting feature. This device's interesting feature would be the pen.
Of course, nothing else is known for sure, such as when this will actually be available. But with renders leaking, it shouldn't be too far off.