PDCD1 and cancer: Nevertheless, the phase III SKYSCRAPER-02 study revealed that treatment of tiragolumab plus atezolizumab plus chemotherapy did not prolong the PFS (HR 1.08; 95% CI 0.89–1.31) and OS (HR 1.02; 95% CI 0.80–1.30) compared with placebo plus atezolizumab plus chemotherapy in patients with extensive-stage SCLC, suggesting that there may be heterogeneity of efficacy of anti-TIGIT plus anti-PD-1/PD-L1 in different cancers [122].