The primary efficacy analysis of overall response rate (ORR) will be interpreted as follows: 1) if less than 9 partial response (PR) or complete response (CR) are recorded, the combination of nab-paclitaxel and pembrolizumab provides less than additive effects and is not likely to be clinically superior compared to pembrolizumab alone based on an ORR assessment; 2) however, if 9 or more PR or CR are recorded, the treatment combination warrants further clinical study. This could take the form of an extended phase II (to reach the 97 patients calculated from the model) or a phase III study.