Lung cancer, as a multistep and multifactorial disease, is among the most fatal cancers worldwide. As new therapies are developed and early screening increases, patients tend to experience progression-free survival (PFS) as a coexistence of living and dying simultaneously. The aim of this study was to explore the awareness context experienced by Chinese elderly patients and family members. Interviews were conducted with 20 interviewees, including 13 elderly patients with lung cancer and 7 caregivers that were recruited using purposive sampling. Semistructured, face-to-face, in-depth interviews were conducted using a qualitative descriptive approach. Ambiguity was commonly experienced by patients with lung cancer with PFS. Three themes emerged from the data analysis: "ambiguity in cancer diagnosis," "ambiguity in prognostic awareness," and "ambiguity in identity." In this case, ambiguity refers to a situation or context in which patients are uncertain about whether there will be a recurrence of their cancer and when it might occur. The findings highlighted that patients experienced ambiguity in response to unclear diagnoses, uncertain prognoses, and identity crises during PFS. Healthcare teams should be equipped with psychosocial knowledge and communication skills to manage ambiguity in diagnosis and prognosis for patients with PFS.