Tiragolumab Plus Atezolizumab Versus Atezolizumab in the Treatment of Stage II Melanoma Patients Who Are ctDNA-positive Following Resection

This study\'s hypothesis is that patients with stage II melanoma who test positive for circulating tumor DNA are at a higher risk for recurrence and therefore adjuvant treatment is justified. In this study, the blood of consenting and eligible patients will be tested for ctDNA and those patients who test positive will be randomized on a 1:1 basis to either treatment with atezolizumab and tiragolumab or atezolizumab alone during Stage 1 of the study. If at least 3 patients in the atezolizumab + tiragolumab arm are shown to be ctDNA negative at C3D1, stage 2 of the study will begin enrollment. Stage 2 consists of 25 patients all enrolled to the atezolizumab + tiragolumab arm (no randomization and no atezolizumab monotherapy arm).Patients who test negative for ctDNA will be observed off protocol.