For me personal this is a pretty hard MU, i got stomped multiple times by @STORM179. But in general i think this is a pretty even matchup overall.
When i get a knockdown it feels always to start playing a round of rock, paper, scissors and most of the time i lose. 
I talked in the “GG’s” thread, how i feel about that matchup and Storm had some nice advice for me.
IMO to boil this MU down is you have to really get into the other players head. i mean you can probably say that about every MU, but for me it’s even more important in this one. Because the main moves/strategies that both characters will use counter each other pretty well: Thunder wants to get in -->Hisako has far reaching normals → Once Thunder got past that he wants to keep up the pressure on wakeup → Hisako can counter that → Thunder can command grab that → Rock, Paper, Scissors!
I dont feel comfortable at all in that match and my explanation might seem pretty simple and superficial, but in my head this is how the match goes and you dont really need to know much more. Of course every information you have beyond that will help (AD-animations, spacing, etc.) but in the end it comes all down to the Counter/Grab/Hit-Game.