A Study of LY3381916 Alone or in Combination With LY3300054 in Participants With Solid Tumors

Inclusion Criteria: * Dose escalation phase: Participant must have histological or cytological evidence of a diagnosis of cancer that is advanced and/or metastatic. * Dose expansion B1: Metastatic TNBC participants who have not received prior PD-1/L1 treatment. * Dose expansion B2: Metastatic NSCLC participants who have progressed on prior PD-L1/L1 treatment. * Dose expansion B3: Metastatic clear cell carcinoma RCC who have progressed on prior PD-L1/L1 treatment. * Have adequate organ function. * Have a performance status (PS) of ≤1 on the Eastern Cooperative Oncology Group (ECOG) scale. * Are able and willing to provide required, newly acquired tumor biopsies. * Have discontinued previous treatments for cancer. * Are able to swallow capsules. Exclusion Criteria: * Currently enrolled in a clinical study. * Have known symptomatic central nervous system metastases or carcinomatous meningitis. * Have a serious concomitant systemic disorder. * Have a symptomatic human immunodeficiency virus infection or symptomatic activated/reactivated hepatitis B or C. * Have a significant cardiac condition. * Have previously received an indoleamine- 2,3-dioxygenase (IDO) inhibitor. * Have an active autoimmune disease or currently require immunosuppression of \>10 milligrams of prednisone or equivalent per day. * Have interstitial lung disease or (noninfectious) pneumonitis, participants with a history of (noninfectious) pneumonitis that required steroids to assist with management.