Tumor metastasis is a primary cause of death among solid tumor patients. Interventions such as chemotherapy with cytotoxic drugs and other targeted therapies focusing on specific genes or tumorigenesis can induce tumor shrinkage in most cases. However， these interventions do not substantially prolong the lives of patients. In recent years， immunotherapy has made significant breakthroughs in treating solid tumors with the introduction of immune checkpoint inhibitors （ICIs）， following the clinical use of Ipilimumab， the first anti?tumor drug with ICIs initially approved in 2011. Currently， four types of ICIs including CTLA?4， PD?1， PD?L1， and LAG3 have been clinically applied and have demonstrated specificity towards more than 20 types of solid tumors. The significance of ICIs lies in their superiority to conventional drugs in three aspects： （1） They can prolong the survival of late?stage patients and even achieve “clinical cure”； （2）They allow patients with rare tumors access a pan?tumor treatment based on specific biomarkers； and （3）They can free a majority of patients from invasive surgical approaches to preserve organ functions， thereby improving patient’s quality of life. This article provides a summary of multiple clinical research projects and explores the clinical evidence derived from the notable achievements related to the three advantages.