Is MySQL 5.7.19, as I understood, after installation it is set up. All settings default, including query_cache_type = 0. For me it was a surprise.
I rarely do a setup. Last time I did it about 5 years ago at least, on older versions in General. Then I remember there set up different cache parameters depending on the load profile. But I do not remember such that the cache has ever been disabled. Without him always (at least used to) all inhibited.
While mysqltuner says everything is OK:
[OK] Query cache is disabled by default due to mutex contention on multiprocessor machines.
The query cache is deprecated as of MySQL 5.7.20, and is removed in MySQL 8.0. Deprecation includes query_cache_type.
What does that mean? Caching now no longer used? For the second hour looking for information on a subject, anything sensible I can not find.