Immune response is constituted of a set of complicated processes in
a quite complex system. Extreme complexity of the
system, and a rather partial knowledge of the basic reactions and processes involved justifies a phenomenological
approach to the modeling of the systems dynamics. We propose a sufficiently general framework for such modeling,
based on delay-differential equations with only two most relevant variables. In a way of an illustration, we describe a
model of the immune response to immunogenic tumors. The model gives consistent predictions for the values of the
relevant parameters estimated from real data.