Pazopanib With or Without Pembrolizumab for Metastatic Soft Tissue Sarcoma

Pembrolizumab will be given for a maximum of 2 years i.e. a total of 35 cycles of pembrolizumab with the q3 week dosing. Participants who complete study intervention after 2 years of pembrolizumab can be treated with pazopanib monotherapy based on physician's judgement. The duration of optional pembrolizumab crossover treatment will be maximum of 2 years i.e. a total of 35 cycles of pembrolizumab for patients progressing on pazopanib.