Basket Study to Evaluate the Therapeutic Activity of Simlukafusp Alfa as a Combination Therapy in Participants With Advanced and/or Metastatic Solid Tumors

Inclusion Criteria:

Participants who have progressed on at least one previous regimen of anticancer therapy (chemotherapy, mutation targeted therapy, and/or CPI therapy)
Measurable disease, as defined by RECIST Version 1.1
Eastern Cooperative Oncology Group (ECOG) Performance Status 0 or 1 or Karnofsky Performance Score greater than or equal to (>=) 70
Life expectancy of >=12 weeks
Confirmed at least one tumor lesion with location accessible to safely biopsy per clinical judgment of the treating physician.

Biopsies are not applicable to participants in Cohorts G, H, K, and L presenting with a single target lesion and absence of any non-target lesion.

Consent to provide an archival tumor tissue sample (if available, applicable to all participants)
Willingness to undergo baseline and on-treatment tumor biopsies for pharmacodynamics (PD) biomarker analysis (biopsies are optional for Cohort A)
Adequate cardiovascular function as defined in the study protocol
AEs related to any previous radiotherapy, chemotherapy, or surgical procedure must have resolved to Grade less than or equal to (<=) 1, except alopecia (any grade) and Grade 2 peripheral neuropathy
Adequate haematological, liver, and renal functions.

Participants with unilateral pleural effusion (indications other than NSCLC) are eligible if they fulfill both of the following:

NYHA Class 1
Forced expiratory volume 1 (FEV1) and forced vital capacity (FVC) >70% of predicted value; participants with lung metastases should present with DLCO >60% of predicted value.
Participants with Gilbert's syndrome will be eligible for the study
Participants must have had confirmed diagnosis of recurrent or metastatic squamous cell carcinoma head and neck, or esophageal cancer or metastatic, persistent or recurrent squamous cervical cancer.

Exclusion Criteria:

Symptomatic or untreated central nervous system (CNS) metastases
History of treated asymptomatic CNS metastases as described in the protocol
Spinal cord compression not definitively treated with surgery and/or radiation or previously diagnosed and treated spinal cord compression without evidence that disease has been clinically stable for >=2 weeks before enrollment
Leptomeningeal disease
An active second malignancy
Penetrating tumor infiltration
Evidence of significant, uncontrolled concomitant diseases that could affect compliance with the protocol or interpretation of results
Episode of significant cardiovascular/cerebrovascular acute disease within 6 months before study treatment administration
History of significant vascular disease (for example, aortic aneurysm, aortic dissection)
Active or uncontrolled infections
Human immunodeficiency virus (HIV) or Active Hepatitis A, B, C, D or E infection (HAV/HBV/HCV/HDV/HEV).
Severe infection within 4 weeks before study treatment administration including, but not limited to, hospitalization for complications of infection, bacteremia, or severe pneumonia.
History of chronic liver disease or evidence of hepatic cirrhosis
Dementia or altered mental status that would prohibit informed consent
History of, active or suspicion of autoimmune disease
History of idiopathic pulmonary fibrosis, pneumonitis (including drug-induced), organizing pneumonia (bronchiolitis obliterans, cryptogenic organizing pneumonia, etc.), or evidence of active pneumonitis on screening chest computed tomography (CT) scan. History of radiation pneumonitis in the radiation field (fibrosis) is permitted
Bilateral pleural effusion confirmed by X-ray
Any other diseases, metabolic dysfunction, physical examination finding, or clinical laboratory finding that give reasonable suspicion of a disease or condition that would contraindicate the use of an investigational drug
Concurrent therapy with any other investigational drug
Immunomodulating agents as described in study protocol
Chronic use of steroids
Last dose with any cytostatic treatments < 28 days before study treatment administration
Radiotherapy within the last 4 weeks before start of study treatment administration, with the exception of limited field palliative radiotherapy
Administration of a live, attenuated vaccine within 4 weeks before Cycle 1 Day 1 or at any time during the study and 5 months after the last dose of atezolizumab
Major surgery or significant traumatic injury <28 days before study treatment administration (excluding fine needle biopsies) or if wound healing has not completed after surgery or anticipation of the need for major surgery during study treatment
Known hypersensitivity to any of the components of the simlukafusp alfa drug product or atezolizumab drug product
Severe dyspnea at rest or requiring supplementary oxygen therapy Locally curative options are available for participant's disease.