My Pathway: A Study Evaluating Herceptin/Perjeta, Tarceva, Zelboraf/Cotellic, Erivedge, Alecensa, and Tecentriq Treatment Targeted Against Certain Molecular Alterations in Participants With Advanced Solid Tumors

General Inclusion Criteria: * Life expectancy greater than or equal to (≥) 12 weeks * Histologically documented metastatic cancer (solid tumors, not including hematologic malignancies) * Participants who have received standard first-line therapy for metastatic cancer (except for the tumors for which no first-line therapy exists) and in whom a trial of targeted therapy is considered the best available treatment option. Eligible participants should not have available therapies that will convey clinical benefit and/or are not suitable options per the treating physician's judgment * No previous treatment with the specific assigned study drug or any other drug sharing the same target * Measurable disease by RECIST v1.1 * Eastern Cooperative Oncology Group Performance Status (ECOG PS) score of 0 or 1 (For patients enrolling in the atezolizumab arm, ECOG score must be documented within 7 days prior to first treatment and confirmation of ECOG PS must be entered into the interactive web response system \[IWRS\] prior to initiation of treatment) * Adequate hematologic, renal, and liver function as defined by the protocol * If applicable, use of contraception methods or abstinence as defined by the protocol Study-Drug Specific Inclusion Criteria: Trastuzumab plus Pertuzumab * Molecular testing results from clinical laboratory improvement amendments (CLIA)-certified laboratories (using tissue and/or blood) demonstrating HER2 overexpression or amplification. Participants must have one…