ABSTRACT
Immunotherapy has opened a new era in cancer treatment. Drugs represented by immune checkpoint inhibitors have led to important breakthroughs in the treatment of various solid tumors, greatly improving the survival rate of cancer patients. Many types of immunotherapeutic drugs have become widely available; however, their efficacy is variable, and relatively few patients with advanced cancer experience life-altering durable survival, reflecting the complex and highly regulated nature of the immune system. The research field of cancer immunotherapy (CIT) still faces many challenges in pursuing the broader social goal of "curing cancer." Increasing attention has been paid to strengthening the understanding of the molecular or cellular drivers of resistance to immunotherapy, actively exploring more effective therapeutic targets, and developing combination therapy strategies. Here, we review the key challenges that have emerged in the era of CIT and the possible solutions or development directions to overcome these difficulties, providing relevant references for basic research and the development of modified clinical treatment regimens.