* High performance/scientific computing
* Graphics
* Infrastructure (web servers and browsers, OS's, drivers, etc)
* Any desktop apps that are CPU/memory intensive. think image processing, video editing, even office applications
* Finance
* Games
* AI. GPUs are becoming more popular for training machine learning models, and C and C++ are pretty much dominating this space with OpenCL, CUDA, etc.
You mentioned in previous comments that browsers and stuff don't really count because you're not going to be implementing a browser that competes with the big four. But people have to work on maintaining those browsers. Same with MS office, Photoshop, etc.
The world pretty much runs on C and C++. From the steering column in your car to the computational fluid dynamics models that predict hurricanes and save lives, to the telephone switches that route your cell phone calls. Until pretty much every important piece of digital technology, small or large, switches over to a new language, there will be a need for C and C++ developers.