When it comes to tumor immunology, understanding of molecular pathways is rather important. During oncogenesis, many molecules should be taken in consideration altogether in context of a single malignancy. It is of a great significance to determine whether these molecules act synergistically or contrary, whether to understand a malignant disease more thoroughly, or even more important, to reveal new approaches of therapy. In this review, we discuss whether and how IL-33/ST2 and PD-1/PDL axis involve in antitumor immunity.