• Provision of signed and dated, written Informed consent form (ICF) prior to any trial-specific procedures, sampling, or analyses

• Patients ≥18 years of age at the time of signature of the ICF

• Part I (dose escalation):

⁃ -Patients with a confirmed diagnosis of advanced, unresectable, and/or metastatic solid tumours (any type)

⁃ For whom no therapy of proven efficacy exists, or who are not amenable to standard therapies.

⁃ Must have measurable lesions according to Response Evaluation Criteria in Solid Tumours (RECIST) v1.1

⁃ Previous treatment with an anti-programmed cell death 1 (receptor) (PD-1) monoclonal antibody (mAb) is allowed as long as the last administration of the anti-PD-1 mAb on the previous treatment is a minimum of 60 days prior to starting treatment in this trial.

• Part II (dose expansion):

‣ Patients must have measurable disease per RECIST v1.1 criteria, must have at least 1 tumour lesion amenable to biopsy, and must be medically fit and willing to undergo a biopsy before first treatment (if adequate archival tissue is not available) and, unless clinically contraindicated, after 6 weeks on therapy.

⁃ Dose Expansion Cohorts: Patients with a confirmed diagnosis of advanced, unresectable, and/or metastatic solid tumours of one of the following types:

• Second and 3rd line Non-small cell lung cancer (NSCLC) patients:

‣ Must have progressed on anti-PD-1 or anti-programmed cell death ligand 1 (PD-L1) treatment after having achieved radiologically confirmed benefit (minimum of stable disease)

⁃ Must have had a minimum duration of benefit of 4 months and minimum treatment duration of 2 months on the previous anti- PD-1 or anti-PD-L1 treatment without experiencing disease progression during that period.

⁃ The anti-PD-1- or anti-PD-L1-containing treatment must have been the latest treatment regimen prior to enrolling in this trial

⁃ Must be within \>4 and \<12 weeks since the latest treatment and their first dose in this trial. Patients who have had anti-PD-1 or anti-PD-L1 monotherapy as their first-line NSCLC treatment regimen must have a PD-L1 expression level of ≥1% at baseline (local validated testing).

∙ Anti-PD-1 or anti-PD-L1 treatment-naïve patients with microsatellite stable Metastatic colorectal Cancer (mCRC):

‣ Patients must have had ≥ 1 line treatment

⁃ Must have microsatellite stable disease (identified using any validated test)

⁃ Must be anti-PD-1 and anti-PD-L1 treatment naïve

∙ Anti-PD-1 or anti-PD-L1 pretreated patients with any high Tumour mutational burden (TMB) (≥10 mutations/Mb) and/or Microsatellite instability high (MSI-H) and/or DNA MMRd solid tumours

‣ Patients must have high TMB (≥ 10 mutations/Mb) and/or MSI-H and/or DNA mismatch repair deficient (MMRd) (measured using any validated test).

⁃ Patients must have received 1 prior anti-PD-1 or anti-PD-L1 treatment regimen.

∙ 1st-line squamous or non-squamous NSCLC patients:

‣ Patients must be treatment naïve

⁃ Must be epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) wild type (only applicable to patients with non-squamous NSCLC)

⁃ Regardless of PD-L1 expression level. However, the number of patients with high level of PD-L1 expression (≥50% PD-L1) will be limited to a maximum of 10 patients

• Eastern Cooperative Oncology Group (ECOG, R01-0787) score: 0 to 1

• Life expectancy of at least 12 weeks after the start of the treatment according to the Investigator's judgement

• Male or female patients. Women of childbearing potential (WOCBP) and men able to father a child must be ready and able to use highly effective methods of birth control (that result in a low failure rate of less than 1% per year when used consistently and correctly) during trial participation and for at least 6 months after the last administration of trial medication. A list of contraception methods meeting these criteria is provided in the patient information.