?An advanced alien race threatens to enslave Earth in the 1500?s and humanity?s last hope lies in the unproven inventions of an Italian Renaissance artist who holds a dark secret.?

Everyone here is spot on. Put Davinci in your logline and I have already purchased my ticket...

>>>reminds them a lot like the movie ?Cowboys and Aliens?. Not sure if that?s good or bad.

That depends. The story hook for "Cowboys and Aliens" is that an alien invasion is set in the past instead of the present. So it's bad in that setting your story in the past is not exactly a new twist on the alien invasion trope.

However, it's good in that the protagonist is the Renaissance genius, Leonard da Vinci, a polymath.? So the success of the story hinges on how well you develop the character, how ingenious his solutions are.

As a side note, more than one people whom I showed this logline to said this storyline reminds them a lot like the movie "Cowboys and Aliens". Not sure if that's good or bad.