The input current of a CMOS gate is mainly due to the reverse-biased junctions
of the input protection diodes, which is absolutely negligible at room temperature
(order of < 0.1nA) but will rise exponentially with temperature to 175C (maximum
junction temperature of most silicon devices). The datasheet input leakage specs are
usually given for the chip's whole temperature range (which may be upto 125C or so).
1uA leakage worst-case at 125C isn't unremarkable, but the room-temperature leakage
will be many orders of magnitude less unless the input diodes have been damaged.
Without protection diodes the leakage current is perhaps < 1pA. But the device would
be destroyed by touching the pins.