Tumor response and disease progression for solid tumors are mainly based on the Response Evaluation Criteria in Solid Tumors (RECIST) criteria, which were designed for non-immunotherapy agents. In the era of immunotherapy, it is well recognized that the tumor size kinetics are not well captured using the same RECIST categories. Immunotherapies have shown some unusual response and progression kinetics, such as "pseudo" progression, or delayed response. In early oncology compound development, objective response rate, disease control rate and early tumor size changes are commonly used as early efficacy metrics for decision-making. The predictive value of these metrics has been demonstrated for traditional chemotherapy and target therapy trials. However, for immunotherapy trials, it is unclear whether these early efficacy metrics are still predictive of survival. Based on several randomized immunotherapy studies, we evaluate the predictive value of early tumor size changes and RECIST-based efficacy metrics. Various time points and cut-off values for early tumor shrinkage to predict survival are explored. Recommendations on the choice of early efficacy metrics are to be discussed.