Immanuel Kant crops up within Hegel's Phenomenology when Hegel communicates with readers about "categories." These were heavily researched and organized by Kant, who was a German predecessor of Hegel's. Kantian categories are extremely important in the development of the Western mind since they are about knowledge and mind, and include concerns about how human consciousness relates with external reality. As such these are intimately involved with the question, "Can we know anything? If so, how?" Answering this question is mandatory for scientific progress, and also for Hegelian philosophy.
The Phenomenology of Mind