Another example is basket trial testing of programmed cell death protein 1 (PD-1) blockade in patients with deficient mismatch repair (dMMR)/microsatellite instability-high (MSI-H) tumors, which confirmed that dMMR can predict the response of solid tumors to PD-1 blockade; this trial has led to the regulatory approval of pembrolizumab for dMMR patients, regardless of cancer origin (53). The gene discussed is PDCD1; the disease is cancer.