Abstract
The recent study by Hodi et al. published in the Journal of Clinical Oncology has evaluated unconventional response patterns during PD-1 inhibitor therapy using immune-related response criteria (irRC) in comparison with RECIST1.1, which constitutes an important step to further understand immune-related response phenomena. This commentary discusses the key observations in the study in terms of their implications and pitfalls, and describes unmet needs that remain to be addressed. The article also emphasizes the important role of tumor response criteria as a "common language" to describe the results of cancer treatment, and discusses future directions for further advances of the field of immuno-oncology.