II. To explore the composition of immune infiltrates in tumor specimens/biopsies from primary and/or metastatic/recurrent sites with selected markers including (but not limited) to cluster of differentiation (CD)4+, CD8+, forkhead box P3 (FoxP3), CD25, lymphocyte activation gene-3 (LAG-3), T cell immunoglobulin mucin-3 (TIM-3), and inducible T-cell co-stimulator (ICOS) and their correlations to objective response, PFS and OS in nivolumab-treated patients.