From my personal experience, PHP is going nowhere. Especially for my personal customers, I cannot use anything but PHP, because it is the right degree of just right for the task and available at all major hosters here.
From my perspective, languages which are in demand in the industry, though, are Java and JavaScript. There is no corporation which does not need Java devs for their servers. And JavaScript (NodeJS)? It's used in parallel for PoCs, small low-load servers and tooling/automation.
Hence, I recommend not throwing PHP away, but also taking a look at the great Frameworks there (for example Laravel). On top of that, also take a look at Spring Boot for Java and Express on NodeJS for JavaScript