Cancer treatment has long been a hot topic of research and the main goal of that is to eliminate cancer cells in the human body. Therefore, many mechanisms have been found to induce tumor cell death, including apoptosis, autophagy, ferroptosis and other programmed cell death (PCD). In addition, targeting cell metabolism and regulating epithelial-mesenchymal transition (EMT) are desirable for developing therapeutic approaches in cancer. Even though these mechanisms mentioned above play a pivotal role in tumorigenesis and tumor progression, they can also change the immune microenvironment and affect the efficacy of immunotherapy. For example, the tumor cells undergoing PCD process might release cytokines and inflammatory modulators, recruiting surrounding nontumor cells to establish a microenvironment for malignant tumors. In addition, the metabolic crosstalk between different tumor compartments strongly contributes to the harsh tumor microenvironment and ultimately impairs immune cell fitness and functions, and EMT may attract immunosuppressive cells or promote the expression of immunosuppressive checkpoint molecules, leading to a tumor immunosuppressive microenvironment.

Immunotherapy represented by immune checkpoint inhibitors (ICIs) has definitely emerged as unprecedented breakthroughs in cancer treatment. However, the fact that many tumors respond poorly and even have primary or secondary drug resistance to ICIs, significantly limits the application of ICIs. It is critical and urgent to gain further insight into the mechanisms of drug resistance and develop new therapies to overcome drug resistance. ICIs in combination with molecular targeted therapy, chemotherapy, or radiotherapy may exert synergistic antitumor activity, which are the current research hot spots and trends of cancer treatment.

In this special issue, all article types are welcome including original research articles, review articles, clinical trials, case reports, commentaries, correspondence articles, short reports, etc.