Key Inclusion Criteria:

• • Subject has Eastern Cooperative Oncology Group (ECOG) performance status 0-1.
• • Subjects who received prior immune-stimulatory antitumor agents, such as anti-PD-1, anti-PD-L1, anti-CTLA-4, OX-40, CD137, etc. are eligible.
• • Histologically or cytologically confirmed, locally advanced or metastatic solid malignancy and has exhausted all the available standard therapy or is not a candidate for the available standard therapy.

Select Tumor Types (COM701 monotherapy cohort expansion; COM701 in combination with a PD-1 inhibitor):

• • Breast cancer (TNBC): Histologically confirmed incurable, advanced estrogen receptor-, progesterone receptor-, and human epidermal growth factor receptor 2 (HER2)-negative (triple-negative) adenocarcinoma of the breast, as defined by the American Society of Clinical Oncology-College of American Pathologists (ASCO-CAP) guidelines. Disease recurrence or progression during or after at least one systemic treatment that included an anthracycline and/or a taxane in the neoadjuvant, adjuvant, or metastatic setting. Subjects must have progressed after a poly ADP-ribose polymerase (PARP) inhibitor for patients with deleterious or suspected deleterious germline breast cancer susceptibility gene (BRCA) mutated metastatic breast cancer.
• • Endometrial cancer: Subjects with locally advanced or metastatic endometrial cancer, Disease recurrence or progression during or after prior therapy that included platinum-based chemotherapy.
• • Ovarian cancer: Disease recurrence or progression during or after prior therapy that included: surgical resection, platinum agent, PARP inhibitor (for subjects with deleterious or suspected deleterious germline BRCA-mutated advanced ovarian cancer or as a maintenance therapy for subjects who have had complete or partial response to platinum-based therapy).
• • NSCLC: Documented stage IIIB or IV or recurrent NSCLC, Disease recurrence or progression during or after prior treatment that included: platinum agent, targeted therapy such as a TKI (if with biopsy-confirmed cytogenetic mutation eg EGFR, ROS, BRAF).
• • CRC (microsatellite stable, KRAS mutation)
• • For Phase 1a monotherapy expansion and Phase 1b only: subject has at least one measurable lesion that could be followed during the study according to RECIST v1.1.

Key Exclusion Criteria:

• • Active autoimmune disease requiring systemic therapy in the last 2 years prior to the first dose of COM701.
• • Symptomatic interstitial lung disease or inflammatory pneumonitis.
• • History of immune-related events that lead to immunotherapy treatment discontinuation.
• • Untreated or symptomatic central nervous system (CNS) metastases.
• • Impaired cardiac function or clinically significant cardiac disease, including any of the following: a) Unstable angina pectoris = 6 months prior to first scheduled dose of COM701; b) Acute myocardial infarction = 6 months prior to first scheduled dose of COM701.