This is a study to evaluate the efficacy and safety of belzutifan monotherapy in participants with advanced pheochromocytoma/paraganglioma (PPGL), pancreatic neuroendocrine tumor (pNET), von Hippel-Lindau (VHL) disease-associated tumors, advanced wt (wild-type) gastrointestinal stromal tumor (wt GIST), or advanced solid tumors with hypoxia inducible factor-2 alpha (HIF-2) related genetic alterations. The primary objective of the study is to evaluate the objective response rate (ORR) of belzutifan per response evaluation criteria in solid tumors version 1.1 (RECIST 1.1) by blinded independent central review (BICR).

Substudy 03C is part of a larger research study that is testing experimental treatments for renal cell carcinoma (RCC). The larger study is the umbrella study (U03).

The goal of substudy 03C is to evaluate the safety and efficacy of experimental combinations of investigational agents in participants with clear cell renal cell carcinoma (ccRCC) who have recurrent disease during or after anti-programmed cell death 1/programmed cell death ligand 1 (PD-\[L\]1) adjuvant therapy.

This substudy will have two phases: a safety lead-in phase and an efficacy phase. The safety lead-in phase will be used to demonstrate a tolerable safety profile for the combination of investigational agents. There will be no hypothesis testing in this study