Immune factors such as cytokines, chemokines, and growth factors are known to play important roles in the preimplantation interactions and communication between the blastocyst and receptive endometrium. This crucial dialog occurs during the stages when the blastocyst is in the uterine cavity immediately preceding implantation and the establishment of pregnancy. Human preimplantation processes are difficult to study due to restrictions on tissue availability. This review focuses on the expression and role of immune factors in human blastocyst-endometrial dialog during the very early stages of implantation. It highlights the importance of immune regulators and the need to develop new models to study human implantation.