Inclusion Criteria:  Tumor histologies:  Dose Escalation: Patients with histologically proven, unresectable, locally advanced or metastatic solid cancers that are considered to express EGFR  Cohort Expansion:  NSCLC that has progressed during or following treatment with platinum-based chemotherapy and an anti-PDx therapy NSCLC with EGFR mutation or ALK rearrangement must have progressed following available EGFR or ALK targeted therapy in addition to treatment with platinum-based chemotherapy HNSCC that has progressed during or following treatment with an anti-PDx (unless ineligible, e.g. patients failing chemotherapy and PD-L1 CPS < 1) and platinum-based chemotherapy (unless ineligible/intolerant of platinum-based chemotherapy) for metastatic or recurrent disease  CRC  K-Ras WT: Patients who have progressed during or after, or are ineligible for, both irinotecan and oxaliplatin based chemotherapy and who are relapsed or refractory to at least 1 prior systemic therapy that included an anti-EGFR antibody K-Ras mutant: Patients who have progressed during or after, or are ineligible for, both irinotecan and oxaliplatin based chemotherapy ECOG performance status of ≤ 1 Measurable disease as per RECIST v1.1 criteria and documented by CT and/or MRI Patients must allow acquisition of existing archival tumor sample, either a block or unstained slides. Patients are required to consent for paired tumor biopsies: one in the screening period and on during the first cycle of treatment Acceptable laboratory parameters and adequate organ reserve Patients who have previously received an immune checkpoint prior to enrollment must have checkpoint inhibitor immune-related toxicity resolved to either Grade ≤ 1 or baseline Patients with symptomatic central nervous system metastases must have been treated, be asymptomatic for ≥ 14 days, and must not have concurrent treatment or concurrent leptomeningeal disease / cord compression  Exclusion Criteria:  Patients with a history of known autoimmune disease with certain exceptions Patients with clinically significant cardiovascular / vascular disease Patients with clinically significant inflammatory gastrointestinal disorders Patients with clinically significant pulmonary compromise Major surgery or traumatic injury within 8 weeks from the date of first study dose Unhealed wounds from surgery or injury Treatment with radiation therapy < 2 weeks from the date of first study dose Inflammatory process that has not resolved for ≥ 4 weeks from the date of first study dose