A Study to Investigate LYL845 in Adults With Solid Tumors

Inclusion Criteria:

* Age ≥ 18 years up to ≤ 75 years at the time of informed consent
* Confirmed diagnosis of melanoma, non-small cell lung cancer (NSCLC), or colorectal cancer (CRC) that is metastatic or locally advanced or unresectable and is relapsed and/or refractory (R/R) after standard therapy for each tumor histology
* Participants must have received prior systemic treatment for their metastatic disease or locally advanced disease based on tumor type as follows:
* Melanoma: participants with disease progression following an immune checkpoint inhibitor (CPI)
* NSCLC: participants with disease progression following at least 1 approved systemic therapy, including an immune CPI-containing regimen for appropriate patients or an approved targeted therapy for known molecular abnormalities if applicable to their disease
* CRC: participants with disease progression following at least 1 line of therapy, including a fluoropyrimidine with oxaliplatin or irinotecan. Microsatellite instability (MSI) high/mismatch repair deficient (dMMR) CRC participants must have disease progression following systemic therapy with immune CPIs.
* Measurable disease including at least 1 lesion that is safely resectable AND a target lesion to measure response and an additional lesion for biopsy
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
* Adequate organ and marrow function
* Women of childbearing potential must have a negative pregnancy test at screening
* All participants must agree to practice highly effective methods of contraception
* Fully recovered from toxicity from prior systemic anticancer therapy

Exclusion Criteria:

* Prior treatment with adoptive cellular therapy
* Prior solid organ transplantation
* Central nervous system (CNS) involvement of disease that is extensive, symptomatic or untreated, or patients with leptomeningeal disease
* Uncontrolled or symptomatic pleural effusion or ascites
* Untreated or active systemic infection
* Active autoimmune disease requiring treatment or primary immunodeficiency syndrome
* Systemic corticosteroids at a dose of \>10 mg of prednisone or equivalent per day
* Other primary malignancy within 3 years prior to enrollment
* Impaired cardiac function or clinically significant cardiovascular disease
* Required chronic anticoagulation, such as warfarin, low molecular weight heparin, or Factor Xa inhibitors
* Pregnant or nursing (lactating) women