WARNING: The following contains spoilers for My Hero Academia Season 5, Episode 4, "Make It Happen, Shinso!" now streaming on Crunchyroll, Funimation and Hulu.
Hitoshi Shinso wants nothing more than to be a Pro Hero, yet is not a part of the Hero course at U.A. That may be about to change though. In Season 5, Episode 4, Shinso gets an opportunity to showcase how much he's improved in a tryout for the Hero course. When Classes 1-A and 1-B fight against each other for combat training, he is added into the mix with them. And though some students think of Shinso's inexperience as a handicap, others see him as an asset thanks to his Quirk, which is what makes him more intimidating. It's also undergone some changes since we last saw him in action in Season 2.
Shino's Quirk is Brainwashing, which puts his targets into a state where they have to obey whatever he commands, as long as it's a clear and precise action. Unfortunately, this power can only be activated when the target verbally responds to something Shinso says. So, if his opponent knows what his Quirk is, all they have to do is ignore Shinso and proceed to attack.
Additionally, the state that Shinso puts his opponents in can be dismantled by a physical shock to the body. We saw this back in Season 2, Episode 20 "Victory or Defeat" when Midoriya breaks his own fingers and is shocked out of his trance. After that, he's able to defeat Shinso. Shinso's Quirk also doesn't work when he uses a microphone -- somehow the transference of sound waves negates the effect of his Brainwashing. So his Quirk, while definitely daunting, needs specific circumstances in order to work to its full effect.
But as of Season 5, Episode 4, Shinso is sporting a new look and, thanks to the guidance of Eraserhead, has new skills to test out with the students in the Hero course. Firstly, he has a new mask that hides his mouth completely and has controls on the sides. This mask is Shinso's new Artificial Vocal Chords, a mechanical device that can mimic other people's voices. This handy new device, along with some well-timed skills, means that Shinso can more easily trick his opponents into responding to things that he says, especially in a group situation like Episode 4's.
Shinso is also now wrapped in a long scarf, similar to his mentor Eraserhead. Eraserhead taught Shinso the fighting style that allows him to use Capturing Weapon, which transforms the seemingly innocuous scarf around his neck into a tool that can grab and restrain things, which improves Shinso's overall mobility. Capturing Weapon, in addition to Shinso's Artificial Vocal Chords, has elevated his ability to use his Quirk effectively, improving both his skill and his potential to be a Pro Hero.
From what we see in Episode 4, Shinso's Quirk is more of an asset than a handicap. While he's still getting used to the new scope of his Quirk, Shinso is practicing with way more experienced students and yet can hold his own. Shinso's inclusion in the Class 1-A team for the first battle was one of the contributing factors to their win. So while he's still acclimating to his new skills and learning how to use them in practical scenarios, he's well on his way to earning himself a place in the Hero course.