An old-school private investigator, assisted by his tech-savvy daughter, investigates the alleged death of the son of a presidential candidate only to uncover a deep conspiracy that puts them in the crosshairs.

Possibly true about the odd couple if that is the case.

I still can't see how this case will be any more interesting than the many other PI's case. I think it needs personal stakes and clear motivation from a good inciting incident.

"Old school" dad vs "tech savvy" kid--what's being set up is an odd-couple relationship to enliven the story. So I think it belongs in the logline. Maybe something like:

An old-school private detective must enlist the help of his estranged, tech-savvy daughter to solve the murder of the son of a presidential candidate. (24 words, 150 characters)

The daughter is only an ally and doesn't need to be in the logline even though she is in the story because it is essentially the PI's plot.

Be specific about the "...deep conspiracy..." reason is investigating stuff is what a PI does most days so what about this PI's investigation is interesting is the conspiracy not the investigation.

Secondly what is the inciting incident? What out of the normal sets the PI off on his way to take action? As it stands the logline doesn't describe a plot because it has not starting point or inciting incident and has no end point or goal. The logline describes a day in the life of a generic PI but how will this be different to the many other PI stories?

A future re draft should answer these questions.

Hope this helps.