As a result of intratumoral injection of Trp, indoleamine 2,3‐dioxygenase 1 (IDO1) which is overexpressed in many different type of tumor cells and causes immunosuppression via Trp metabolic pathway[35] will be exhausted, leading to accumulating Trp and the Trp/miR complex as we demonstrated in this study. Here, IDO1 is linked to neoplasm.