Someone posted this mechanics last month:

Widowmaker Hopping Mechanic. (Jumping and Scoping

Which in itself is pretty powerful mobility, achieved with holding down the Secondary Fire throughout.

However, it is not quite optimal, since the scope-in is cancelled by the jump command, which causes a delay before the rifle is allowed to scope in. This method only allows a shot to be fired every second jump, and the shot is charging only on the downward airtime.

To enhance this, simply releasing the scope before issuing the jump command allows instant re-scoping:

Sequence:
Fire & Unscope -> jump -> Re-scope -> [shot charging] -> repeat.

Implications
Instead of firing on every second jump, you are now firing on every jump. Also, instead of charging only on the falling airtime, you are charging your shot the whole time you are in the air.

However, this can only achieved if you execute the sequence flawlessly. The rhythmic requirement seems to have stringency akin to advanced mechanics in CrazyRacing KartRider. I couldn't do it quickly enough myself, but I would expect in the hands of a pro player, this could potentially be extremely oppressive.

(I've also posted this on Reddit)