Microsoft found out that it is developing a game controller for the smart tablet

Microsoft is in the development of the "physical controller that can be used in the smartphone-tablet", and has already prototype is created, media "dealing with the Windows of information Windows Central has reported that".

Microsoft Research has prototyped Xbox controllers for phones and tablets | Windows Central
https://www.windowscentral.com/microsoft-research-prototyping-xbox-controllers-phones-and-tablets

Report: Microsoft Is Prototyping Controllers For Phones And Tablets - Game Informer
https://www.gameinformer.com/report/2018/10/28/report-microsoft-is-prototyping-xbox-controllers-for-phones-and-tablets

In October 2018, Microsoft announced " Project xCloud ", a game streaming service that allows you to play from any device anytime, anywhere. Project xCloud aims to be able to play games of your choice not only from PCs and game machines, but also from smartphones and tablet PCs.

Project xCloud, a service that allows Microsoft to play games streaming from any device at any time - GIGAZINE

According to the Microsoft Research article obtained by Windows Central, Microsoft is trying to provide quality similar to home gaming devices with "Project xCloud", but many games do not correspond to touch panel input of smartphone, Inevitably an input delay will occur.

So, Microsoft Research seems to have focused on mobile game machines equipped with physical controllers such as Sony's PlayStation Portable (PSP), Nintendo's Nintendo DS and Nintendo Switch, buttons and joysticks.

Even though there have been controllers of type to be worn on smartphones, Microsoft Research evaluated them as "bulky and not flexible". Based on ergonomics, I designed "Xbox controller for smartphone" from 1 and printed it with a 3D printer and made it. The project itself seems to have started in 2014, but it seems that full-scale efforts began taking into consideration that Nintendo Switch was a huge success .

The new controller looks like the following. It is possible to divide in the center, fix it so as to pinch the smartphone or tablet. The grip part seems to be removable. Charging is done by inserting it into the charging dock with the left and right controllers split.

Not only Microsoft, Google and Nintendo are also embarking on game streaming service. However, while other services require a specific web browser and dedicated game hardware, Microsoft's Project xCloud is a big feature of being able to play without choosing the environment, such as smart phones and tablets. To that end, development of a physical controller for smartphones and tablets seems to be an essential task for Microsoft.