Tumor micro-environment (TME) encompasses a wide range of complex interactions between tumor stroma, tumor cells, and immune cells. The infiltration of cancer cells by immune cells is receiving widespread attention as cancer progression is shaped by the dynamic equilibrium between cancer cells and infiltrating immune cells. Although our understanding of the roles of immune cells in cancer proliferation, invasion, and treatment continues to progress, there are many unknowns in this field. Recent techniques such as single-cell sequencing as well as several computational methods have provided new insights into the composition of infiltrating immune cells. As a result, there is an emerging interest to advance understanding of the roles of infiltrating immune cells in cancer.

This Special Issue aims to investigate the composition and functions of infiltrating immune cells in solid tumors. We aim to highlight the subsets of infiltrating immune cells which play critical roles in the development of cancers. We invite submissions exploring the molecular mechanisms of how tumor cells might be influenced by infiltrating immune cells either by direct contact or by secreting cytokines. We also invite research focusing on the alterations of infiltrating immune cells in immunotherapy, radiotherapy, and chemotherapy, and their effects on treatment outcome. We hope this Special Issue can provide a multi-perspective view of infiltrating immune cells and bring new insights to improve the prognosis of cancer patients. We welcome both original research and review papers.

Potential topics include but are not limited to the following:

• Composition of infiltrating immune cells
• Special subsets of infiltrating immune cells
• Effects of infiltrating immune cells on cancer cells
• Effects of infiltrating immune cells on other immune cells or microenvironment
• Roles of infiltrating immune cells in cancer proliferation, invasion, and metastasis
• Roles of infiltrating immune cells in tumor escape from immunosurveillance
• Roles of infiltrating immune cells in immunotherapy
• Roles of infiltrating immune cells in radiotherapy, chemotherapy, or other treatment
• Effects of cancer cells on infiltrating immune cells
• Potential targets of immunotherapy