What is hijacking and anti-hijacking of standard essential patents?

In the practice of intellectual property rights, people often talk about technology patenting and patent standardization. There is also a saying that "third-rate enterprises make products, second-rate enterprises make brands, and first-rate enterprises make standards", in which the so-called standards refer to having the necessary patents for standards. Standard essential patents refer to patents that are included in international standards, national standards and industry standards and must be used when implementing standards. There is excessive patent here, that is to say, it is suspected of monopoly.